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BY Will Wills

How many times have you heard a guy claim his 350 made 400hp and then watched him tick off a 17-sec quarter mile? Yawn. Why am I not impressed by the creeping pace of mainstream hotrod technology?

Lets go back to 1974, the last year of the Musclecar Era. The last year of the factory thumper and the beginning of the performance dark age where 200hp 460s gave way to 120hp 302s.

In 1972 the US automakers tossed out their old method of running stripped down engines on their dynos to get the biggest figures they could for their advertising. Now, everyone was testing the same way and in a realistic way with air filters, exhausts, and accessories on and running. Horsepower numbers taken after ’71 tend to be much more believable and level between manufacturers.

The hot cars of the period were the 340 Duster, the 455 Super Duty Trans Am, the Chevy Z28 and the 351C HO and Cobra Jet Mustangs. During the switch to SAE figures, these cars had lost, on average 20% of their rated power. Some people claim that the drop in compression was to blame, but that just isn’t so—mostly, the loss was through redefinition.

For one thing, the 100 octane required to run those pre-’71 factory hotrods just wasn’t being put into them at the pump. You had to fill up with hi-test for Saturday night. Sure, the point or two some of these engines lost from ’71 to ’72 played a part, but all things being equal, the post ’72 cars I mentioned were better off with the point of compression knocked off. In fact, I have built two motors that came with 10.5-1 and 11.0-1 compression and I lowered both of them with dished pistons so I could run pump gas.

So while in theory, these ’72-’74 factory rods should have made a little less power, they didn’t run like it. In fact, the ’73 Super Duty Trans Am is said by some to be the fastest car of the era.

So in ’75 the Dodge W2 heads, Super Duty Pontiac, the Cleveland four barrel, the Z28 all hit the dumpster; carbureted performance never to return to Detroit and Dearborn. Now the focus was on killing emissions with high restriction, lean burning heads; restrictive EGR and air injection systems and the dreaded catalytic converter.

Now, with the dark ages over, all of these clunky 70’s and 80’s V8 engines are out in the junkyard and can be bought by the pick-up load, if anyone would want one of them.

Even in the good years, the factory ‘rods did not use the same junky cylinder heads as your plain Jane’s used. The factory ‘rods came with deep gears, solid lifters, 4-speeds and heads capable of flowing thousands of rpm past what the standard engines were capable of. Enter your 400hp, 350 guy.

You can’t take a marginal engine, bolt on a cam, intake, carb and headers and run with an old Z28 or 351C HO Mustang. Let alone out perform it. And check out how well those old factory hotrod engines did:

A good way to compare the relative performance of an engine is to calculate its average operating pressure (MEP). To do that, you throw its horsepower, displacement and rpm into a formula and come up with a psi figure that means nothing, but is a good tool for comparison.

For instance, the ’72 351C HO was exactly the same solid liftered, high revving engine as the ’71 Boss 351, except it had lost 2 points of compression, was rated at 266hp @ 5400 rpm and its MEP works out to 111psi. The ‘73 455 Super Duty Trans Am with its 310hp @ 4800rpm works out to 113psi. The worst of the best is the solid liftered 350 Z28 with its 245hp @ 5400 rpm coming in at 103psi. And the best is ’72 340 Duster with 240hp @ 4800rpm and 117psi. Let’s call 115psi a great running carb’ed engine; and take my word for it that 97psi is a typical garden variety carb’ed engine—with the 4bbl versions just making their bad numbers at higher rpms.

I expect that the 400hp 350 is probably capable of 220hp @ 5000rpm with a carb-cam-intake kit and headers. Am I doing the bolt-ons an injustice? No, its better than a 2-bbl if you swap out the rear axle gearing. But garden variety heads don’t flow. They are junk. If you want to catch up with and maybe pass the old factory super-stars, buy some aftermarket heads that are designed to flow. Or, even better, move on.

I said the automotive dark ages were over. Check out these two examples of pushrod V8s with multi-port electronic fuel injection and you will see what I mean:

The typical 225hp 5.0 Mustangs has a MEP of 141psi. Its nemesis, the 305hp LT1 Trans-Am posts a MEP of 133psi. Pretty impressive. And things keep getting better. Four valves-per cylinder naturally aspirated motors are getting into the 160psi range running 10-1 compression—that’s about where the 2.3 turbo started out. Flat amazing if you consider how hard it is to keep a 9.0-1 carbureted engine from detonating under hard use and at 50% less cylinder pressure.

So do I want to hear about 200hp, 400hp 350s? No. I’ve owned a few of those, too. If you want to be impressive, move up to electronic fuel injection, four-valves per, forced induction, sophisticated nitrous oxide set-ups with bottom ends that can take it or just absolutely astound me with cubic inches—like 600 or so. ‘Cause frankly, we have been seeing the same damn engines in the popular magazines since I was a kid. ~TRS

Have a rant? E-mail me at wwills@iquest.net, or contact me via PM, and I might just let you put it here!