Big-Block vs. Small-Block V-8: What’s the Difference?

Big-block or small-block—which one is best? When this is the question, it matters whether you're trying to win a drag race, or just a simple bar bet. You may be trying to come to a consensus to bulk up your gearhead knowledge or you may be building a period-correct street machine with a ton of power from an engine that matches the emblem on the fender. Do you already have a heavy favorite and want to back up an opinion, or are you a novice with an open mind and a thirst for hard facts? If you're a student of domestic 20th-century V-8 engine architectures, you've come to the right place because we've got answers.

Big Pump vs. Little Pump

Engines in their simplest form are air pumps. The bigger the displacement of the pump, the greater the potential power; when all things are equal, the bigger the engine, the greater the power output. Unfortunately, in the argument of big-block vs. small-block, things aren't equal, and our basic argument of "bigger is better" kind of hits the guardrail in a few places. First is the availability of aftermarket cylinder heads with high-flowing port shapes and large valves. The availability of these varies wildly for different engine families, when it exists at all. Moreover, the cost of parts may make building some engine brands cost-prohibitive at larger sizes and higher hp, so while you may crave a 455ci Oldsmobile big-block, for example, you may be better off with a new-era Chevy LS at half the cost per-hp. The 455ci Olds might have more cubes, but a 327ci (5.3-liter) LS is the better air pump of the two. Already, you've learned that the size of the air pump isn't a marker for how well it pumps air.

Big Valve vs. Small Valve

From left to right: Buick, Olds, Pontiac, and Chevy small-block cylinder heads

If engine size doesn't solve the big-block vs. small-block question, what else matters? If your eyes have wandered down the page to the large chart labeled "Small-Block vs. Big-Block Specs," you can get your first clue from the "intake valve" spec column, which shows the most common intake valve diameter size for each engine family. The intake valve is the door through which air enters the engine. Big doors move more air than small doors, so it's possible to have an engine with plenty of displacement but only modest-sized valves—a description that fairly describes most of the OE engines on our list. So long as the engine speed doesn't exceed a valve's ability to satisfy the engine's demand for air mass, there's no problem. But as soon as the valve and the port presents a restriction, the power party is off. As it turns out, 20th-century big-block engines (and even small-blocks) hit this wall with relatively little effort.

Here we run the risk of oversimplification, because valve size is a stand-in for mass flow and port flow quality, but it's instructive because the valve diameter is largely dependent on bore diameter. The bigger the bore, the bigger the valve you can use and the more power you can make, provided the port can support the flow. In the big-block vs. small-block debate, the availability of high-flow, big-valve aftermarket heads and intake manifolds is a make-or-break proposition, so unless the debate is stock vs. stock the aftermarket has a say in crowning winners and losers.

Big Bore vs. Big Stroke

If increasing the bore and increasing the stroke both provide more cubic inches and presumably more power, does it really matter how the factory went about increasing the displacement? It turns out, that does matter. A look at the "Small-Block vs. Big-Block Specs" chart shows stock bore, stroke, and approximate engine weight, and here you'll note that some engines have larger bores and shorter strokes (oversquare) while others have smaller bores and longer strokes (undersquare). A short-stroke engine doesn't need as tall a deck height to make the same cube-count and will typically weigh less, setting up a lighter-is-better argument. This favors the big-block Chevy, a fact somewhat hidden by the reality that the big-block Chevy cast-iron heads and intake are super heavy, though they are easily replaced by lighter aluminum. The stock BBC heads are massive, but in aluminum form, this giant footprint on the fire deck adds stability and more flexibility in port design which the aftermarket has taken full advantage of.

Ford Performance A460 big-block cylinder case

Where a taller-deck big-block V-8 has the advantage is in situations where the bore is also larger. The Chrysler 440 and the Ford 460 had no interdivisional rivals like GM, so pattern-makers could make everything bigger; more bore diameter, more deck height, more clearance for stroker cranks, and more valve diameter. The Ford 385-series big-block and the Chrysler 440 wedge paid a modest weight penalty without really being any more powerful from the factory than Chevy offerings (the 427ci Chevy L88 claimed 430 hp, the Chrysler 440ci Six Pack claimed 390 hp, the Ford Super Cobra Jet 429 claimed 370 hp), but their internal architectures hid a lot of potential that wouldn't be revealed until well after the muscle car era was over and aftermarket companies joined the fray. Here is where things get very interesting—but before we cover these Ford and Mopar interlopers we need to wade through the GM big-block vs. GM small-block scrum.

Survey Says: Big-Block Chevy

Dart's Big-M big-block Chevy cylinder case

If you just want to win races while spending the least amount of money, get a modern Chevy LS small-block. Debate over. You're just not going to get to four-digit power levels with anything else for less than the price of an LS, but that's no fun for the purposes of our old-school 20th-century big-block vs. small-block slugfest. We're cutting to the bottom line early so we can ponder the deeper mysteries of the big-block vs. small-block debate. But when it comes to making copious power from any common domestic V-8, the big-block Chevy wins hands down, not so much on the basis of any overwhelming mechanical merit, but because the aftermarket has been continuously working on making the big-block Chevy bigger, badder, and better for the past half-century. In fact, the aftermarket is so influential that many of the best big-block Chevys don't have any Chevy parts in them at all (this goes as far back as the Drag Race Competition Engine, or DRCE, which was fielded by Oldsmobile beginning in 1983).

GM Big-Blocks vs. GM Small-Blocks

Pontiac "big-block" 428ci V-8

If we set aside the outsized advantage that the big-block Chevy has by way of the performance aftermarket, it's instructive and fun to look at the some of the more esoteric aspects of the various big-blocks and small-blocks made by Detroit's automakers through the muscle car era. In this way, we can evaluate winners and losers by various criteria, both as-conceived, in production form, and in later, aftermarket-enhanced form. These engines didn't exist in a vacuum; they needed to fit in the space available, meet production cost requirements, and in some cases, abide by arbitrary corporate limitations.

Oldsmobile 403ci small-block on the dyno

At General Motors for instance, a rule was set up in 1963 for mid-sized cars that engine size limits were not to exceed 330ci, resulting in a bunch of small-blocks just under that size (Chevy 327ci, Pontiac 326ci, Olds 330ci), then changed its mind in 1968 with a 350ci limit (Chevy 350, Buick 350, Olds 350, Pontiac 350). In 1965, GM allowed, and then limited, big-block engines in mid-size and smaller cars to less than 400ci (Pontiac 389, Olds 400, Chevy 396, Buick 400), until they didn't, starting in 1969. Even then, GM only cracked open the tap for a few 427ci Chevy Camaro COPO orders (Corvette was always exempt). By 1970, all size limits at GM were gone, with displacements swelling to 454ci (Chevy) and 455ci (Buick, Olds, Pontiac). With GM holding its divisions under a cube limit for most of the era, it's no wonder the competition seemed so close on paper.

Cost vs. Power

The small-block Chevy reigns supreme as aftermarket parts leader for V-8 engines.

With any big-block vs. small-block comparo, one of the major debate points is cost-savings (the small-block) versus big power (the big-block). With the Chevy engines, the aftermarket has erased much of the disparity here, making both big-block and small-block engines around the same in terms of hp-per-dollar. The big-block has more room inside relative to the small-block, so you can buy more power for the dollar without the cost skyrocketing too much on the high-end of the power range. Likewise, the aftermarket has serviced the small-block Chevy well over the decades, offering stroker kits, high-performance induction, and stronger blocks with clearance for stroker kits, keeping the small-block Chevy well in the competition fray. Building a high-output small-block Chevy really isn't a barrier like it is for many other brands of GM small-blocks, and in some cases the power level of a performance-built small-block Chevy can exceed the power output of some big-block architectures in a cost-effective way, irrespective of displacement.

Big-Block Buick vs. Small-Block Buick

Small-block 350ci Buick V-8

The cost-versus-power face-off makes a more compelling argument with less popular, less well-supported manufacturers. If you're a Buick fan, for instance, you'll quickly discover that it's almost impossible to field a competitive 350ci small-block Buick due to a dearth of power parts for the short-lived engine family. The 350 Buick debuted in 1968 and shared more with the 231ci V-6 than either the earlier "nailhead" big-block or the 400ci big-block released in 1967—it has both its aluminum timing cover and bore diameter in common with the 231ci V-6. An undersquare design (small bore, long stroke) and a small intake valve kept power in check while making the small-block Buick block as wide as a big-block Chevy. (If you're looking for a small underdog Buick to beat Chevys with, you'd do better to build a turbocharged and intercooled 231ci V-6 LC2, as found in the 1986-87 Buick Grand National).

Big-block Buick by Automotive Machine & Performance

The Buick fan looking for the biggest bang for the buck within his own brand will probably want a 455ci big-block, an engine that is supported by a small, loyal cottage industry with companies like Automotive Machine & Performance, TA Performance and Kenny Betts Racing. A big-block Buick also has a modest advantage in the mass department; as a precision thin-wall casting, the big-block Buick cylinder case is the lightest of the era, making it a threat in spite of its modest cylinder head flow profile relative to contemporary offerings. The 455ci Buick was also the torque king of the era, putting out a bona fide 510 lb-ft of torque, the most for its day.

Big-Block Pontiac vs. Small-Block Pontiac

While Buick offered small-block and big-block designs that shared little, Pontiac by contrast built all its V-8 engines from the same basic architecture. Pontiac never added a "big-block" engine family in the late 1950s or early 1960s like others did but rather increased the size of its existing OHV V-8 design. All Pontiac engines between 326ci and 455ci have the same external dimensions, with only internal alterations to bore and stroke. All had the same 6.665-inch connecting rod, and the Pontiac 350ci "small-block" of 1968 was derived from the earlier 389ci V-8, but with a smaller 3.87-inch bore (versus the 389's 4.06-inch bore).

When looking at the cost-versus-power problem through Pontiac glasses, it clearly pays to go big since the cost to build any Pontiac V-8 is essentially the same. Pontiac fans should note that at around the 600hp mark, Pontiac blocks develop a tendency to crack down the valley and require additional measures to provide reliable support in this fatigue-prone area. Pontiac engine builds are well-supported by the tightly-knit but sometimes fractious Pontiac aftermarket community, and include Nitemare Performance, Tin Indian Performance, SD Performance, and Butler Performance. So who wins the big-block Pontiac vs. small-block Pontiac battle? It's the mack-daddy 455ci big-block, but you can always call it a stroked and poked 326 small-block if you like!

Big-Block Olds vs. Small-Block Olds

Big-block Oldsmobile

By 1964, on the eve of the muscle car revolution, Oldsmobile's ground-breaking OHV V-8 "Rocket" design of 1949 was long in the tooth and ripe for redesign. Like Pontiac's V-8, Oldsmobile V-8s would share some elements such as bore center spacing and deck height between its engines, but because Oldsmobile elected to use two different deck heights instead of one it meant designing and manufacturing different cylinder heads and intake manifolds for small-block and big-block versions. This was further complicated by a change in big-block cylinder cases in its 400ci "big-block" in 1968. As a result, building any form of performance Oldsmobile V-8 from the era requires a master's degree in Oldsmobile history from the university of hard knocks.

Oldsmobile 350ci small-block

Helping Oldsmobile fans figure things out is a full-time job for a growing number of Oldsmobile-specific engine builders and parts manufacturers; you can bypass your graduate degree from the school of hard knocks by employing the brainpower of several Doctors of Oldsmobile-ology in the form of Mondello Performance Products, Dick Miller Racing, Rocket Racing and Performance, Supercars Unlimited, Olds Rocket Parts, and this author's personal favorite, BTR Performance. So what engine do we like in the Olds ranks, big-block or small-block? With its oversquare bore and the potential to fit much larger valves, plus its light weight, the small-block Oldsmobile is our favorite of the two. With few options available for truly high-flowing cylinder heads, your money is better spent on the small-block Olds, as the big-block (tall-deck) Olds hits a point of diminishing returns cost-wise much more quickly. Oldsmobile small-block bonus: In 1977, Olds increased the size of the low-deck small-block Olds to 403ci by giving it a fun-sized 4.351-inch bore, then put it under the hoods of Pontiacs and Buicks from 1977 until 1979.

Small-Block vs. Big-Block Specs*

Engine: Bore Dia.: Intake Valve: Stroke: Deck height: Weight: 350ci Small-Block Chevy 4.00 in. 1.94 in. 3.48 in. 9.02 in. 535 - 575 lbs. 454ci Big-Block Chevy 4.25 in. 2.06 in. 4.00 in. 9.80 in. 685 lbs. 350ci "Small-Block" Buick 3.80 in. 1.88 in. 3.85 in. 10.19 in. 450 lbs. 455ci "Big-Block" Buick 4.31 in. 2.00 in. 3.90 in. 10.57 in. 600 lbs. 350ci "Small-Block" Oldsmobile 4.06 in. 1.88 in. 3.38 in. 9.33 in. 500 - 560 lbs. 455ci "Big-Block" Oldsmobile 4.13 in. 2.07 in. 4.25 in. 10.62 in. 605 - 620 lbs. 350ci "Small-Block" Pontiac 3.87 in. 1.94 in. 3.75 in. 10.25 in. 590 lbs. 455ci "Big-Block" Pontiac 4.15 in. 2.11 in. 4.21 in. 10.25 in. 650 lbs. 351ci Ford Small-Block Windsor 4.00 in. 1.84 in. 3.50 in. 9.50 in. 510 lbs. 351ci Ford Small-Block 2V Cleveland 4.00 in. 2.04 in. 3.50 in. 9.20 in. 550 lbs. 428ci Ford Big-Block Cobra Jet FE 4.13 in. 2.09 in. 3.98 in. 10.17 in. 650 lbs. 460ci Ford Big-Block 385-Series "Lima" 4.36 in. 2.09 in. 3.86 in. 10.32 in. 640 lbs. 360ci Chrysler Small-Block LA-Series 4.00 in. 1.88 in. 3.58 in. 9.60 in. 550 lbs. 440ci Chrysler Big-Block Wedge 4.32 in. 2.08 in. 3.75 in. 10.72 in. 670 lbs. Show All

*With apologies to AMC and Cadillac fans, this list is not a comprehensive inventory of all big-block or small-block engines of the muscle-car era, but rather of the largest and/or most common versions of each engine family. GM small-blocks are arbitrarily limited to 350ci to make the list more manageable. Weight of engines in stock configuration is approximate.

GM vs. the World

For many years, the big-block Chevy and the small-block Cleveland-headed Ford Windsor were the top contenders at the Amsoil Engine Masters Challenge.

So far, GM has hogged the spotlight, but the giant hook is about to make an appearance from stage left and pull the warm-up act off stage. Ford and Chrysler were not taking things lightly during the muscle car era, and as sales-volume underdogs, they had nothing to lose. Both Ford and Chrysler developed limited-production Hemi-headed big-blocks (at Ford, the FE-based over-the-counter SOHC 427 and the 385-Series derived Boss 429, at Chrysler the 426ci Hemi), but these were largely out of reach for the average person, and today would require significant amounts of discretionary income to own. For this reason, we only considered the common engine variants in our big-block vs. small-block debate.

Lightness vs. Power

All-aluminum 454ci small-block Ford Windsor with TFS heads and 730 hp

The 1960s saw the predominant use of cast iron in cylinder cases, cylinder heads, and intake manifolds. Inexpensive and strong, cast iron was used almost exclusively, whereas today aluminum alloy and lightweight thermoplastics comprise a significant number of engine components in newer engine families. Then as now, power demands strength, and strength adds mass, the biggest difference being that back in the 1960s, if you wanted strength, it came with a bigger weight penalty. Without considerations of inter-brand rivalry, Ford and Chrysler big-blocks were able to leapfrog GM's big-blocks simply by making them bigger in the areas that counted the most: bore diameter and deck height.

Ford 429ci Cobra Jet 385-series big-block circa 1971

Given the contemporary state of development in 1960s-era airflow technology, the extra internal real estate of the Ford and Chrysler big-blocks didn't pay that big a dividend at the time; it would take the aftermarket to take real advantage. In recent decades the Ford 385-Series "Lima" big-block (429/460ci) and B/RB-series Chrysler Wedge (383/400/440ci) have seen high adoption rates by aftermarket manufacturers and engine builders to the point where they are at cost-per-hp parity with the big-block Chevy up to around 800 hp. Moreover, with a new wave of alloy aluminum blocks, cylinder heads, and intake manifolds (particularly engine blocks), the Ford and Mopar big-blocks can be built to flyweight specs at well over 1,000 hp. In comparing small-block Fords to big-block Fords, and in comparing small-block Mopars to big-block Mopars, aftermarket developments have turned the tide in some interesting ways. Let's take a closer look.

The Battle of Ford V-8s

438ci "Clevor" Ford small-block Windsor with Cleveland-style heads

Once a production engine's useful life to the OEM is over, it gets put out to pasture. As sad as that is, there's no room for sentimentality in the boardroom no matter the brand. With Ford, however, the groundswell of support from gearheads and racers was so great that the aftermarket rescued both the small-block Windsor and the big-block 385-series Ford before they had any time to wither away. In the Ford camp, the rivalry is hot and heavy, with racers seemingly limited only by the cash on hand—far less of a problem when you keep winning races as they tend to do. On the small-block end of things, the 5-liter Fox-body Mustang kept the short-deck (8.2-inch deck height) 302ci Windsor small-block on the boil through the 1994 model year, which had a knock-on effect on its larger 351ci small-block Windsor sibling available in half-ton F-150 trucks. Early on, the airflow necessary to support big power numbers in a small-block Ford came from another Ford small-block, the 351ci Cleveland, which only lived for five years between 1970 and 1974. In recent years, however, canted-valve race versions of small-block Windsor heads (AFR, Edelbrock, Dart) have leveled with the flow advantage of a Cleveland-style head.

The Cleveland Connection

Edelbrock's contemporary SC-1 small-block Ford head with Yates-style chambers and ports

orts

Way back at the top, we told you about the importance of the intake valve, in many ways more important than the displacement volume itself. When Ford designed the Cleveland small-block, it was a concession of sorts to get big-block power out of a small-block sized package. In practice, on a daily-driven car, the Cleveland V-8 had ports that were too large to promote good drivability and low emissions, but for performance, it couldn't be beat. Moreover, so similar were the Windsor and Cleveland that Cleveland-style heads could be adapted to Windsor engines with minimal frustration (note: Don't try this unless you know what you're doing!). This is exactly what led to Ford's dominance in the NASCAR circuit during the 1980s—Cleveland-style ports and chambers on Windsor-based blocks. In this regard, if the story were Ford small-block vs. Chevy small-block, the Cleveland-style head on a small-block Windsor would pummel a SBC with ordinary aftermarket heads (canted-valve SB2 excluded), because as far as the air and fuel is concerned, the Cleveland-headed Windsor is a big-block. Today, Cleveland-style Windsor heads based roughly on the Yates NASCAR model are available along with high-flow Windsor heads, and you'll find small-block Fords of this ilk in contention at nearly every major big-money heads-up drag race or engine-building competition.

The Super Cobra Jet Connection

Jon Kaase Racing P-51 big-block Ford 460 head

Were this the only surprise in Ford's bag, we could stop right here and claim the small-block Ford the victor over the big-block Ford, but history had other plans. In full anticipation of the next round of the muscle car power wars, Ford laid the groundwork for the 1970s with the 385-series big-block, the successor to the aging Ford-Edsel (FE) line of big-blocks. When the Super Cobra Jet 429 landed in 1969, it was already a technical generation ahead of the Chevy 454 that would come the following year. With huge bores on giant bore centers, a vertiginous deck height, and a high cam tunnel for a He-Man-sized stroke, it was ready-made for what never came from the factory: a proper set of cylinder heads. Though the Super Cobra Jet head was adequate for the street at the time, it needed help. That help eventually came years later, thanks to Jon Kaase and his company, Jon Kaase Racing Engines. Kaase in fact did the original work for Ford Racing in the early years getting the Super Cobra Jet head right, further developing it after that tenure.

AFR's next-generation Bullitt cylinder head for the Ford 429/460 385-series big-blocks.

In the modern era, besides JKRE, the big-block 385-series Ford is supported by serious competition-oriented cylinder heads and intake manifolds from AFR, Ford Performance, and Trick Flow Specialties. When it comes to making over 800 hp with a stock truck block, you won't be doing it with a big-block Chevy, but you can with a Ford 460. The good news is, for naturally-aspirated power levels up to around 850 hp (thanks to the hard work of a few companies) the stroked big-block Ford 429/460 has similar cost-per-hp to a production-based big-block Chevy or big-block Chrysler 440 Wedge.

Big-Block Ford vs. Small-Block Ford

Jon Kaase-built Ford 460ci big-block crate engine.

Once Ford performance got yanked off the OE assembly line and put into the care of racers, the Ford camp would flourish in the wake of guys like Glidden, Roush, Elliot, Nicholson, and Yates. Choosing the victor in a big-block Ford vs. small-block Ford battle is hard because either is going to produce the desired result at a price the average enthusiast can still manage. Big- and small-block Fords may not be littering the ground like LS engines, but there are enough for them to be a commodity in a buyer's market, and built out at a price competitive with similar small-block and big-block Chevys. In this instance, big-block Ford vs. small-block Ford is a tie in hp-per-dollar terms.

In This Corner: the Small-Block Chrysler

The LA-series engine first appeared in 1964 model-year Chrysler cars as a 273ci unit. It was loosely based on Chrysler's earlier '50s-era "A" engine but was trimmed down for its new role as a lightweight thin-wall-cast small-block. The 273ci was joined in 1968 by 318- and 340ci versions, which retained the 273's 3.31-inch stroke but increased the bore from 3.625 inches to 3.91 inches (318ci) and 4.04 inches (340ci). In 1971, the stroke increased to 3.58 inches with a 4-inch bore to produce the 360ci LA-series small-block. In the breathing department, the LA-series small-block is well supported by Brodix, Edelbrock, Speedmaster, Indy Cylinder Head, and in prior years by Mopar Direct Connection with its race-only W-2 cylinder head. In framing the battle of small-block Chrysler vs. big-block Chrysler, we must consider the strength of the aftermarket, the number of fans wanting to build them, and the number of available engine cores. In this regard, the LA-series Chrysler small-block (as well as its successor, the Magnum series 5.2/5.9-liter) is a popular low-cost choice for a pump-gas-friendly stroker, and Chrysler small-block crate engines are also common.

In This Corner: the Big-Block Chrysler

While most of the engines in our story have wedge-shaped combustion chambers, only the Chrysler big-block is called out as a wedge. Why? This has been done editorially for years to eliminate confusion; when the 350ci big-block wedge came out in 1958, it replaced three lines of hemi-headed engines: the Chrysler FirePower, Desoto FireDome, and Dodge Red Ram. Beginning in 1958, there were successively larger versions of the Chrysler big-block wedge, first as low-deck B variants with a 9.98-inch deck height (350ci, 361ci, 383ci, and 400ci) then with RB versions (383ci, 413ci, 426ci, and 440ci), all having a behemoth 10.72-inch deck height. Mopar followers differentiate the wedge's deck height as "B" (9.98 inches) and "RB" (10.72 inches) to further clarify the engine type (both were made concurrently). There were also B and RB versions of the 383ci, plus 426ci versions of the Hemi and the RB wedge. The only good part about the Chrysler big-block confusion is that, unlike Oldsmobile or Buick, it causes little consternation with identifying and procuring induction components such as cylinder heads.

The history lesson allows us to better understand why the Mopar wedge is still so popular today; there are a lot of wedge big-blocks around because they were made for over two decades. Despite the dizzying array of sizes, there is commonality and progress in the most important area: cylinder heads. In this department, there are plenty of manufacturers making cylinder heads for big-block Chryslers, such as Edelbrock, Indy Cylinder Head, 440Source.com, Trick Flow Specialties, Speedmaster, Brodix, and ProMaxx. What's drawing them to the Chrysler 440? The big-block Chrysler is like the Ford 460 big-block in that it has so much room to put big-stroke cranks and big bores. Both are oversquare designs, meaning their bore diameter exceeds their stroke, allowing valves to effectively feed giant bores. This does several nice things, like managing the stroke for easier balancing and less rod angularity (which leads to wear). With the Chrysler big-block the 10.72-inch deck height gives the piston a lot of compression height (the crown-to-wristpin distance), a must for big strokes and solid reliability. Thanks to the B/RB block's inherent strength and aftermarket induction support, the big-block Chrysler can be built to a magnificent size at a reasonable price—check out Indy Cylinder Head's 572ci big-block Chrysler crate engine rated at 750hp as an example.

Big-Block Chrysler vs. Small-Block Chrysler

For those living in the Mopar world, big-block vs. small-block is less like a debate and more like a mutual support society; budget-minded Chrysler fans enjoy a number of choices for stock and stroker-displacement options in the small-block ranks, with 408ci stroked Magnum-series small-blocks proving to be a popular low-cost choice for compact A-Body cars (Duster, Dart, early Barracuda, Valiant). In the 21st century, the small-block Mopar is near competitive parity with production-based Ford and Chevy small-blocks on a cost-per-hp basis up to around 500 hp, thanks to the many vendors offering upgraded breathing components. But when it comes to making really big power without shelling out for a Hemi, the Chrysler big-block wedge is the cost-effective go-to item for Mopar racers wanting the win light down the stretch. In one sad note, one of the most promising cylinder heads for small-block Chrysler Magnum engines—the hi-po version of EngineQuest's CH318A/B—is no longer being manufactured, making the small-block Magnum one of the few engine families to move backwards.

Who's the Ultimate Winner of the 20th-Century V-8s?

Chevrolet Performance's 632ci 1,000hp big-block Chevy crate engine

At the end of the day, there's no denying the might of the big-block Chevy. As we said up front, the number of classic Chevys, the preponderance of big-block Chevy cores, the number of Chevy fans, the enthusiastic number of manufacturers providing parts, the number of Chevy-specific races, the number of engine builders, and the extensive amount of time of aftermarket development (over a half-century) means that no amount of inherent technical superiority by other brands can overcome the big-block Chevy's advantage. Like we said, the aftermarket has a say and it has spoken. Of course, the premise was to declare a winner of 20th-century V-8s; ultimately, in the 21st century, the big-block Chevy bows to the LS on a hp-per-dollar basis.

Bonus: How to ID Different GM 350ci Small-Block Engines!

Buick: Front-mount distributor with LH offset tilted 30 degrees into timing cover, six-bolt valve covers, aluminum timing chain cover with oil pump, LH fuel pump mount, RH starter mount.

Chevy: Rear-mount distributor goes through the intake manifold, four-bolt valve covers (perimeter bolts through '85, center bolts '86-and-up), RH fuel-pump mount, RH starter mount.

Oldsmobile: Rear-mount distributor goes into block (slightly offset to LH side), inverted fuel pump mounts on RH side (fuel lines connect to the top of the pump), front vertical oil-filler tube into timing cover, 10-bolt valve covers (later covers may only use five bolts), LH starter mount, 12 inches between the heads at the base of the intake manifold (on a big-block Olds, it's 14 inches).

Pontiac: Rear-mount distributor goes into the block (slightly offset to RH side) and rotates counterclockwise, LH fuel-pump mount, air gap under intake with separate valley cover, four-bolt valve covers, LH starter mount.

Watch the Full Episode! Roadkill vs. Mighty Car Mods

Now that you know all there is to know about the differences between big-block and small-block engines, check out episode 60 of Roadkill, where David Freiburger and Mike Finnegan finally got together with Marty and Moog of Mighty Car Mods, Australia's most popular YouTube show for gearheads. The four guys came to an agreement: Roadkill would build the most American car possible for the Mighty Car Mods blokes, and then Marty and Moog would assemble an absurd icon of Mighty Modding for the Roadkill boys. There's no way to imagine the fun that explodes across the language barrier when these four get together for some killer burnouts and mad skids! Watch the full episode right now, then sign up for a free trial to MotorTrend+ to catch up on the rest of the Roadkill catalog!