 Buick 455 , Oct. 01,...  Buick 455 , Oct. 01, 570.5 lb-ft @ 4,600 rpm, 555.4 hp @ 5,500 rpm |
 Chevy 454 , Sept. 01,...  Chevy 454, Sept. 01, 565.1 lb-ft @ 4,200 rpm, 533.2 hp @ 5,600 rpm |
 Ford 460 , May 01, 567.4...  Ford 460, May 01, 567.4 lb-ft @ 4,000 rpm, 528.8 hp @ 5,800 rpm |
 Mopar 440 , Nov. 01,...  Mopar 440, Nov. 01, 582.9 lb-ft @ 4,100 rpm, 535.5 hp @ 5,300 rpm |
 Olds 455 , Oct. 2000 & Feb...  Olds 455, Oct. 2000 & Feb 01 (update), 558.6 lb-ft @ 4,000 rpm, 496.9 hp @ 5,300 rpm |
 Pontiac 455 , Jan. 01,...  Pontiac 455, Jan. 01, 575.3 lb-ft @ 3,600 rpm, 501.3 hp @ 5,200 rpm |
 Except for the Buick, we were...  Except for the Buick, we were able to use Fel-Pro heavy-duty head gaskets on all the engines. Like this Olds version, Fel-Pros heavy-duty line features integral preflattened steel wire O-rings and a steel-core laminate. |
 Affordable Federal Mogul/Speed-Pro...  Affordable Federal Mogul/Speed-Pro forged replacement pistons were used in all six engines, but getting about 10.0:1 compression often required severe block milling. For example, these Mopar 440 Six Pack slugs were installed at a 0.006-inch deck height to achieve 10.23:1 compression. |
 The baseline carb on all engines...  The baseline carb on all engines was a Speed Demon 750-cfm double-pumper. Jetting was optimized for each engine combination. |
 MSD provided its billet distributors...  MSD provided its billet distributors for all the engines including this Olds unit. Triggering was handled by an MSD HVC high- output coil and Digital 7 ignition. |
Back in the classic musclecar era when there was no replacement for raw displacement, octane was high, and fuel was cheap, Buick, Chevy, Mopar, Ford, Olds, and Pontiac each produced large-displacement big-block engines, and benchracers argue endlessly over which one was best. But talk is cheap, so over the last year Car Craft sponsored the buildup of engines from each of these manufacturers using, to every extent possible, commonly available off-the-shelf performance parts.
Subject to real-world parts availability, each motor was built as identically as possible using modern Edelbrock high-flow aluminum heads (except for the Buick, which used TA Performance heads, since Edelbrock has no Buick offering), approximately 10.0:1 compression ratios, aggressive (yet still streetable) Comp Xtreme Energy XE274H hydraulic flat-tappet cams, Hooker Super Competition headers (2-inch primaries x 3-½-inch collectors), Edelbrock Performer RPM intakes (if offered), MSD billet distributors, ARP rod bolts, and a Speed Demon 750-cfm double-pumper carb. The bottom-ends were assembled the same way an average car crafter does it: No exotic parts or niche tricksjust good machining practice, premium Federal Mogul bearings, Speed-Pro piston rings and forged pistons, and (in most instances) Fel-Pro gaskets. Each engine appeared in its own detailed buildup, but here well take a collective look at their similarities and differences.
In terms of raw peak numbers, the Buick 455 performed the best and the Olds 455 the worst. But theres more to the story than just numbers. The Mopar turned in excellent results even though it had the smallest displacement of the bunch. The Chevy and Ford made fairly good numbers, not surprising considering their huge ports and valves. Youd expect the long-stroke Pontiac to be a torque monsterand it wasbut the short-stroke Mopar actually came in a few lb-ft higher. Whats interesting was that except for the big-block Chevy, these engines in the past have always been cylinder-head limited. However in recent years, modern aluminum heads have become widely available for even niche engines. These lightweight castings pack a heavyweight punch, dramatically increasing output, andon typical street engines like theseeliminating the need for expensive (and not always consistent) head-porting.
When the new heads are combined with modern and aggressive, yet streetable, cam profiles, outputs easily exceed 1 hp/ci on 92-octane gas. In fact, given the same compression ratio, cam grind, and similar flowing heads, the engines perform more alike than not. By analyzing the data on these pages, it becomes apparent that any differences in engine output are primarily attributable to variances in cylinder head flow, gross valve lift (caused by different rocker-arm ratios) and cylinder-bore diameter (the Olds and Pontiac are hurt by their relatively small bores). And as good as the power and torque numbers are, most of these engines could really benefit from even more aggressive cam profiles if top-end horsepower is the goal. Moving up to a solid-roller cam with about the same 0.050-inch tappet-lift duration as the hydraulic flat-tappet grinds could bump up power and torque by as much as 50 numbers in some cases without adversely affecting streetabilityalthough it would burn a hole in many of our wallets.
Off-the-shelf piston selection continues to be a problem. For many of the engines, it proved difficult to achieve compression ratios in the low 10s using available replacement pistons without severe block milling. And every one of these engines used heavy replacement-style forged pistons. Switching to lightweight forgings could reap big benefits: The engines would rev up quicker under load, deeper valve notches would provide ample piston-to-valve clearance, and the weight reduction would aid bottom-end longevity. Unfortunately, lightweight forged pistons in streetable compression ratios for big-block engines must generally be custom-ordered, adding a few hundred dollars or more to the costs of these engines.
Edelbrock has really done its homework on its Performer RPM and RPM Air-Gap series of high-rise, dual-plane intakes. Where available, they unfailingly provided the most area under the curve, and computer simulations show theyd run the best e.t.s when installed in a car. Finally, while a 750-cfm carb performed well on our big-blocks, severalparticularly the Buickpulled manifold vacuum on the top-end, indicating theyd benefit from a larger carb. Any of these engines is capable of running quarter-mile e.t.s well into the 11s when installed in a 3,600-pound car with a relatively mild torque converter and rearend gears. Thats in total street trim, except for 10-inch wide drag slicks. Big-blocks forever!