Muscle Car Engine Shootout - Ford Vs. Chevy Hot Small-Block Dyno Showdown - Hot Rod Magazine

Back in the muscle car era, Ford and Chevy slugged it out for small block engine supremacy. But which one actually built the most powerful small block engine? Memories may differ from the actual reality, so naturally a shootout was the only way to properly compare these legendary small blocks. So that's what we did. We built exact replicas of each of the most famous small blocks from back in the day and tested them against each other on the dyno at Westech Performance in Mira Loma, California. Read on to find out which engine won each round.

Year: 1965
Ford Shelby 289 Vs. Chevy L76 327
We begin our four-year Ford vs Chevy shootout in 1965, when Shelby offered a hopped-up version of the Ford Hi-Po 289, while Chevy countered with the now legendary 327. On the surface, the comparison between a 289 Ford and a 327 Chevy seems like a one-sided affair-after all, isn't bigger always better? For power output, bigger is often better, but there was more to the story. It was a pivotal year for Ford and Chevy small blocks in 1965, as Shelby managed to topple the mighty Ferrari with the relatively diminutive Cobra Daytona project. It was the final year of the Fuelie Corvette, as Chevy then offered a big-block as the high-horsepower engine option. On the Ford side, the top offering for the Mustangs and Cobras came from Shelby in the form of its 306hp 289s. Rated at nearly 60 hp less than the 365hp L76 327, the little 289 proved more than adequate in the lightweight Cobras.

Though originally equipped with tri-Y headers, the 289 was run with a standard set of 1 3/4-inch headers designed for a Fox Mustang application. Since we replaced the stock exhaust manifolds on every motor with a set of 1 3/4-inch headers, we wanted to level the playing field. Equipped with the Holley carb and Hooker headers, the Shelby 289 produced 302 hp at 5,800 rpm and 310 lb-ft at 4,600 rpm.

The '65 327 Chevy small block offered more than just displacement, as the L76 (365hp carbureted) 327 came with 11.0:1 compression, compared with 10.5:1 for the Shelby 289. Head flow was also a major issue, as the 461 Fuelie heads offered larger intake and exhaust valves (2.02/1.60 versus 1.78/1.45) and increased port volume. Compared with the Hi-Po Windsor heads on the Shelby motor, the Chevy Fuelie heads offered as much as 30 additional cfm per runner. The Chevy 327 also featured more aggressive cam timing in the form of the legendary Duntov 30-30 stick (reproduction supplied by Elgin). While the lift values were comparable (0.477, Shelby versus 0.485, Chevy), the duration (at 0.050) figures were skewed greatly in favor of the Chevy (254 degrees versus 228 degrees). Both companies featured very effective aluminum, dual-plane, high-rise intake manifolds topped by performance-oriented Holley carbs. The 327 Chevy featured a 780-cfm 3310, while Shelby installed a slightly smaller 715-cfm 4150 on the 289.

We ran two stock, rebuilt small block engines on the dyno using a set of 1 3/4-inch chassis headers and a 750 Ultra HP Holley carb, since locating the pair of matching-numbers carbs was difficult and expensive. With all the advantages, it should not be too surprising that the 327 Chevy small block easily outpowered the smaller 289 Ford. Rated by Chevy at 365 hp and 350 lb-ft, our test motor produced 356 hp at 6,100 rpm and 369 lb-ft at 4,100 rpm. These peak numbers compare with 302 hp at 5,800 rpm and 310 lb-ft at 4,600 rpm for the Ford. Almost no matter where you measured in the rev range, the larger Chevy was up by 50 hp and a like amount of torque over the Ford. While we had the 327 on the dyno, we also managed to run an original factory Rochester fuel-injection setup courtesy of Chuck Smith. Rated 10 hp higher than the carbureted L76, the L84 Fuelie motor produced almost exactly 10 more horsepower than the carbureted version, though it did not manage to reach the rated 375 hp-even with the long-tube headers. It seems that the carbureted and injected 327 engines were a tad overrated by GM, while Shelby was a bit more honest about the power output of the 289.

Ford vs Chevy Specs At A Glance   L76 327 Shelby 289 Displacement 327 ci 289 ci Rated output, horsepower 365 hp at 6,200 306 hp at 6,000 Rated output, torque 350 lb-ft at 4,000 329 lb-ft at 4,200 Bore/stroke 4.0/3.25 4.0/2.87 Compression 11.0:1 10.5:1 2/4 bolt block 2 2 Crank (cast or forged) Forged Cast Rod length 5.7 5.15 Forged rod Forged Forged Head casting No. 461 C50Z-6049-B Chamber volume 61 to 64 cc 52 to 55 cc Valve sizes 2.02/1.60 1.78/1.45 Peak flow rates (intake/exhaust) 210/146 175/126 Screw-in studs Yes Yes Guideplates Yes No Cam hydraulic/solid Solid Solid Cam lift 0.485 0.477 Cam duration (0.050) 254 228 Cam lobe separation 114 114 Intake manifold Dual-plane Dual-plane Aluminum/iron Aluminum Aluminum Carb Holley 3310 4V Holley 4150 4V Carb rating 780 cfm 715 cfm Tested output, horsepower 356 hp at 6,100 302 hp at 5,800 Tested output, torque 369 lb-ft at 4,100 310 lb-ft at 4,600

Year: 1969
Ford Boss 302 Vs. Chevy DZ 302
The history of the Trans-Am series is well documented. Unfortunately, the actual performance, or at least the real power output, of Chevy's and Ford's sub-5.0L street motors is somewhat less so. It seems that every article ever written about either the Boss 302 or the DZ 302 always mentions the same thing: Though originally rated at 290 hp, these 302s made as much as 400 hp. Checking out the spec box, we see that the DZ 302 was essentially a 302ci version of the 365hp 327, sharing the 11.0:1 compression, Fuelie heads, and even the Duntov 30-30 cam. Also present were the aluminum high-rise intake and Holley 780-cfm carb. As impressive as the specs were on the Chevy 302, Ford's Boss 302 stepped up things with a pair of production four-barrel Cleveland cylinder heads that flowed as well as a fully ported set of Chevy race heads of the period. Compared with the Chevy, the Boss 302 was down slightly in compression (10.5:1 versus 11.0:1) and down in cam duration at 0.050 (228 degrees versus 254 degrees) but up in valve lift (0.514 versus 0.485). Both shared impressive induction systems, but the Boss 302 heads allowed it to not only overcome the deficit in compression and cam timing but also actually outperform the Chevy 302.

Once broken in and ready for action, the DZ 302 produced 356 hp at 6,700 rpm and 333 lb-ft at 4,400 rpm. Torque production from the impressive little Chevy exceeded 325 lb-ft from 4,000 rpm to 5,200 rpm.

Our pair of 302ci small-blocks was run at Westech on the Superflow 902 in the same configuration, meaning no accessories, an electric water pump, and 1 3/4-inch, long-tube headers. Both motors were run with the same 750 Holley Street HP-series carburetor used previously on the 327 and 289. Naturally, both motors were subjected to timing sweeps as well.

First on the pump was the Chevy DZ 302. Rated at 290 hp, the DZ 302 pumped out 356 hp at 6,700 rpm and 333 lb-ft at 4,400 rpm. Where the Boss 302 never reached 325 lb-ft of torque production, the Chevy exceeded 325 lb-ft from 4,000 rpm to 5,200 rpm. The Chevy was certainly the king of the midrange.

Much has been written about the huge ports and valves used on the Boss 302, but the little Boss actually produced more torque at 3,000 rpm than the smaller-port DZ motor. Most important to Ford fans, the Boss 302 produced more ultimate power than the Chevy with peak numbers of 372 hp at 6,800 rpm. The peak torque of 324 lb-ft offered by the Boss was down compared with the DZ, but from 5,800 rpm to 7,000 rpm (and beyond), the Boss was the boss.

Specs At A Glance   '69 DZ 302 '69 Boss 302 Displacement 302 ci 302 ci Rated output, horsepower 290 hp at 5,800 290 hp at 5,800 Rated output, torque 290 lb-ft at 4,200 290 lb-ft at 4,300 Bore/stroke 4.0/3.00 4.0/3.00 Compression 11.0:1 10.5:1 2/4 bolt block 4 4 Crank (cast or forged) Forged Forged Rod length 5.7 5.15 Forged rod Forged Forged Rod ratio 1.753:1 1.716:1 Head casting No. 186 C9ZE-A Chamber volume 61 to 64 cc 61 to 64 cc Valve sizes 2.02/1.60 2.23/1.71 Peak flow rates (intake/exhaust) 210/146 274/176 Screw-in studs Yes Yes Guideplates Yes Yes Cam hydraulic/solid Solid Solid Cam lift (gross) 0.485 0.514 Cam duration (0.050) 254 228 Cam lobe separation 114 114 Intake manifold Dual-plane Dual-plane Aluminum/iron Aluminum Aluminum Carb Holley 4150 4V Holley 4150 4V Carb rating 780 cfm 780 cfm Tested output, horsepower 356 hp at 6,700 372 hp at 6,800 Tested output, torque 333 lb-ft at 4,400 325 lb-ft at 4,200

Year: 1970
Ford 351 Cobra Jet Vs. Chevy LT-1 350
It is true that performance was at the forefront during the '60s, but it can be argued that Chevy and Ford were still producing some impressive machinery as they entered the '70s. In 1970, Chevy introduced the legendary LT-1 small-block. Rated at 370 hp (in the Corvette), the 1970 offering took a back seat only to the '65 Fuelie 327 in terms of rated output. At Ford, 1970 also ushered in a brand-new engine family. In the quest to maximize airflow, Ford engineers designed the now legendary Cleveland heads, which would eventually be used on everything from race-winning Boss 302s to the heavy-hauling 400M. The top small-block Ford offering for 1970 was the four-barrel 351 Cobra Jet. Rated at just 300 hp, only the mild cam timing kept the Cobra Jet from becoming a serious boulevard bruiser.

For our factory reproduction LT-1 and 351 Cobra Jet cams, we once again turned to the Elgin catalog. While the Chevy 350 was sporting a solid-lifter cam, the 351 Cobra Jet made do with a milder hydraulic flat-tappet grind.

Much like the previous 302 comparison, Chevy went with wild cam timing and average head flow on its LT-1, while Ford stepped in with serious head flow and mild cam timing. In 1970, the LT-1 350 and Cobra Jet 351 were sporting '60s-era 11.0:1 compression, but the LT-1 managed to retain the solid-lifter cam. For 1970, GM softened the cam timing from the previous Duntov 30-30 used in the '69 DZ 302. Where the Duntov cam offered 0.484 lift and 254 degrees of duration, the new LT-1 grind stepped down the intake lift to 0.459 and the duration to 242 degrees. The exhaust remained the same as the previous Duntov grind, but the combination of increased displacement and milder intake cam timing meant the LT-1 did not offer the frantic top-end charge like the DZ motor. The benefit of the combination was a serious hike in low- and midrange torque (up some 75 lb-ft over the 302). Though the LT-1 offered milder cam timing, it was still considerably wilder than the Cleveland offering from Ford. The Ford cam offered a decent lift value at 0.490 (even better considering it was hydraulic and required no lash), but the intake duration measured only 207 degrees (making the 242 degrees offered in the LT-1 look wild by comparison). The Ford Cobra Jet made up for this relatively mild cam timing with additional airflow to the tune of 50 to 75 cfm over the Chevy. When it comes to making horsepower, airflow is king.

Illustrating the effect of Chevy cam timing versus Ford airflow, we ran the '70 LT-1 and Cobra Jet on the engine dyno. As with all our previous muscle car motors, the Chevy 350 and Ford 351 were both configured with 1 3/4-inch Hooker headers and the Holley 750 Ultra HP carburetor. In this instance, the Ford probably benefited from the carburetor more than the Chevy, as the LT-1 was originally equipped with a 780 Holley, while the Ford featured an Autolite 4300-series carburetor. Equipped with our Holley and Hooker combination, the '70 LT-1 produced 353 hp at 5,600 rpm and 392 lb-ft at 4,100 rpm. Torque production was exceptional from the LT-1, exceeding 375 lb-ft from 3,400 rpm to 4,700 rpm. Once again, the Cleveland head flow all but overcame the cam timing deficiency as the 351 Cobra Jet produced 365 hp at 5,800 rpm but only managed 379 lb-ft at 3,800 rpm. That the 351 Cobra Jet produced peak torque at just 3,800 rpm was an indication of the mild cam timing. Though down on peak horsepower, the LT-1 outperformed the Cobra Jet from 3,300 rpm to 5,500 rpm, meaning an acceleration contest with equal weight and gearing would likely go to the Chevy.

Unlike the aluminum high-rise/Holley combo on the LT-1, the Cobra Jet was equipped with a cast-iron intake manifold designed to accept an Autolite carburetor. Specs At A Glance   '70 LT-1 '70 Cobra Jet Displacement 350 ci 351 ci Rated output, horsepower 370 hp at 6,000 300 hp at 5,400 Rated output, torque 380 lb-ft at 4,000 380 lb-ft at 3,400 Bore/stroke 4.0/3.48 4.0/3.50 Compression 11.0:1 11.0:1 2/4 bolt block 4 4 Crank (cast or forged) Forged Cast Rod length 5.70 5.778 Forged rod Forged Forged Rod ratio 1.637:1 1.651:1 Head casting No. 492/414 D0AE-(G-R) Chamber volume 61 to 64 cc 61 to 64 cc Valve sizes 2.02/1.60 2.19/1.71 Peak flow rates (intake/exhaust) 210/146 274/176 Screw-in studs Yes No Guideplates Yes No Cam hydraulic/solid Solid Hydraulic Cam lift 0.459/0.485 0.481/0.489 Cam duration (0.050) 242/254 207/221 Cam lobe separation 116 115 Intake manifold Dual-plane Dual-plane Aluminum/iron Aluminum Iron Carb Holley 3310 4V Autolite 4300 Carb rating 780 cfm 600 CFM Tested output, horsepower 353 hp at 5,600 365 hp at 5,800 Tested output, torque 392 lb-ft at 4,100 379 lb-ft at 3,800

Year: 1971
Ford Boss 351 Vs. Chevy LT-1 350
Due mostly to emissions regulations, 1971 brought major changes to the GM lineup. Compression ratios were dropped across the board. Gone were the days of the snappy 11.0:1 motors like the '70 LT-1, DZ 302, and L76 327, replaced by a maximum compression ratio of 9.0:1. This meant the hottest small-block offered by Chevrolet in 1971 was a 9.0:1 version of the previous LT-1. Things weren't all bad, as the open-chamber head swap actually improved the airflow and flame travel compared with the small-chamber combo. Our '71 LT-1 test motor was a perfect example of what can happen when you drop compression but increase airflow. The '71 version actually produced more peak power than the high-compression '70 version but lost out in average power lower in the rev range. Unlike GM, Ford maintained the '60s-era high compression for one last year and combined the '70 351 Cobra Jet displacement with the '69 Boss 302 cam timing. The result was nothing short of amazing, as the '71 Boss 351 is actually the most powerful small-block Ford or Chevy ever produced.

The big change for the '71 LT-1 was a drop in compression ratio from 11.0:1 to 9.0:1. This was accomplished with a flat-top piston and 76cc combustion chambers.

Many of the high-performance parts were carried over from the '70 LT-1 to the '71 version, including the solid lifter cam, 2.02/1.60 valve combination, and high-rise induction system. In fact, the only major change was the aforementioned drop in compression ratio brought about by the installation of flat-top pistons and an increase in combustion chamber size from 64 cc to 76 cc. In subsequent years, the compression ratio on the performance small-blocks would drop even farther. By contrast, the '71 Boss 351 motor retained the 11.0:1 compression ratio introduced on the '70 351 Cobra Jet. Additional changes for the Boss 351 included a Cleveland version of the solid lifter Boss 302 (Windsor) cam profile. The Boss 351 also received an aluminum version of the four-barrel Cleveland intake manifold, designed to accept the new 4300D spread-bore carburetor. Rated at 715 cfm, it offered more airflow than the previous 4300A used on the 351 Cobra Jet. To maintain consistency in our testing, we ran the Boss 351 with the same 750 Holley using an early standard-bore intake manifold. If anything, the (nearly impossible to locate) aluminum Boss 351 intake might be worth a few horsepower, but (according to early Ford engineers) all the four-barrel Cleveland intakes are said to perform equally.

Given the combination of Boss 302 cam timing and 351 Cobra Jet displacement, we had high hopes for the Boss 351. We finally had a motor with enough displacement, compression, and cam timing to take advantage of the airflow offered by the four-barrel Cleveland heads. We were every bit as eager to see how much the drop in compression hurt the '71 LT-1 compared with the '70 version. It is interesting to note that both of the 1971 offerings from Ford and Chevy were factory rated at 330 hp. First up on the dyno was the '71 LT-1, equipped as always with the Holley 750 Ultra HP and 1 3/4-inch Hooker headers. After minor tuning and a timing loop, we were rewarded with peak numbers of 359 hp at 5,900 rpm and 376 lb-ft at 4,100 rpm. The final small-block in our test was the '71 Boss 351, which produced an amazing 383 hp at 6,100 rpm and 391 lb-ft at 4,000 rpm. Torque production exceeded 375 lb-ft from 3,300 rpm to 4,700 rpm, showing the big ports and valves on the four-barrel Cleveland heads can be made to work in the lower rev ranges when combined with the right cam and compression. With 383 hp, the baddest small-block of the muscle car era was actually produced in 1971.

Ford did not follow GM by reducing the static compression ratio on its hottest small-block for 1971. The Boss 351 was still sporting 11.0:1 compression thanks to small combustion chambers and a slight dome on the forged pistons. Specs At A Glance   '71 LT-1 '71 Boss 351 Displacement 350 ci 351 ci Rated output, horsepower 330 hp at 5,600 330 hp at 5,400 Rated output, torque 360 lb-ft at 4,000 370 lb-ft at 4,000 Bore/stroke 4.0/3.48 4.0/3.50 Compression 9.0:1 11.0:1 2/4 bolt block 4 4 Crank (cast or forged) Forged Cast Rod length 5.70 5.778 Forged rod Forged Forged Rod ratio 1.637:1 1.651:1 Head casting No. 487 D1ZE-B Chamber volume 74 to 76 cc 64 to 67 cc Valve sizes 2.02/1.60 2.19/1.71 Peak flow rates (intake/exhaust) 217/151 274/176 Screw-in studs Yes Yes Guideplates Yes Yes Cam hydraulic/solid Solid Solid Cam lift 0.459/0.485 0.514 Cam duration (0.050) 242/254 228 Cam lobe separation 116 114 Intake manifold Dual-plane Dual-plane Aluminum/iron Aluminum Aluminum Carb Holley 3310 4V Autolite 4300D Carb rating 780 cfm 715 CFM Tested output, horsepower 359 hp at 5,900 383 hp at 6,100 Tested output, torque 376 lb-ft at 4,100 391 lb-ft at 4,000