In one respect, you can't really compare equal-rated horsepower engines from different manufacturers. I know, it should be possible, but it doesn't always work that way. Especially when one factory rating has more real horsepower than the other one. Throw in different axle ratios, tires, and not quite the same vehicle weights. If one is more torque-oriented, it'll do better at lower rpms than one that's more mid-range/top end oriented. So, to me, what should be an equal pairing really doesn't come out that way.
And, sometimes the OEM tire choice was important as all rubber compounds aren't the same. For example, the '68 and prior C-bodies usually went through the road test handling tests with ease, but in '69, Chrysler was using a particular "upgrade" Goodyear tire that did not respond well in cornering AND the Saginaw power steering pump couldn't keep up with demands of the slalom (i.e., "pump catch" happened), which made them slower compared to other cars. Not good! Tire choice CAN be more important than you might suspect.
In the particular case of the 396, it had a spreadbore Rochester Q-jet carb as standard equipment. All 750 cfm of it! While the Chrysler's AFB was probably more like 600cfm or a bit less. But the Chevy exhaust was usually more restrictive than anything Chrysler ever built. Trade-off?
The fuel economy tests the magazines did back then were not really consistent between publications OR test drivers. So you had to look at the progression within each magazine rather than compare one to the other. Route and driving style were important, but even moreso now with EFI. CAR LIFE tested a '67 Fury 383 4bbl convertible (normal 3.23 axle ratio and *.55x14 tire size, all standard equipment for that model year). Nominal fuel economy was 14 on the highway, which I considered low. But then my '67 Newport 383 4bbl might have edged-out about 16 on trips (even with different carb/intake combinations aimed toward efficiency). Not quite as much as our '66 Newport 383 2bbl would do.
Key thing is that don't expect a less restrictive air cleaner to magically decrease the 1/4 mile ETs by .90 second or more. It might sound like it is, but . . . .
In EVERY engine design, there is one major restriction of sorts. Be it valves sizes, intake port sizes, exhaust manifold design, exhaust system design (Chrysler was usually better than GM or Ford at that), or carb size. In that continuum of things, the air cleaner is a somewhat minor player, to me, but a "contributing factor", too. Many tend to equate intake sounds to power, louder is more powerful, but that doesn't have to be the case.
MUCH of our automotive experiences are based on auditory and tactile "feels". Unsilenced air cleaners give more auditory rewards, generally, but with a quieter intake system of equal flow, you might suddenly wonder how you got to be going so fast so quickly (as you didn't hear anything happening to indicate such).
Of course, there's also that "push you back in the seat" feeling, but softer foam padding and weaker seat support springs might enhance that feeling too!
Back then, MOTOR TREND was usually the gold standard of car magazines. Just as HOT ROD was for "hot rods". Both from the old Petersen Publishing Co. CAR LIFE had a former Chrysler engineering person on their road test staff. They were usually more consistent in their tests, too. I usually felt like Chrysler products got a "better shake" from them, by observation, but they did well by all makes, too. BTAIM
IF you want to find a plethora of old magazine road tests and other factory-based information, head on over to
www.wildaboutcars.com. Road tests, factory brochures, factory performance information, parts books, service information, etc. But the coverage varies from model year to model year and brand to brand. But a '72 Imperial-size load of car stuff and information, there! In order to get to the "deep dive" stuff, you might have to online registration and possibly become an archives' member (for a small fee), but you DO get a lot for the money. Kind of like Hamtramck Historical on steroids, but not just for Chrysler products.
The only way to do your research is to do it. Then you'll increase your personal knowledge base and continue on to more such research. Hopefully, there's funding! We've all been there, a time ago, I suspect.
Enjoy!
CBODY67
