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I'm sure this subject has been kicked around, probably to death, but I was wondering if anyone of the C3 Heroes out there have converted a 1976 Corvette hood to FUNCTIONAL cowl induction and possibly any performance gains? I guess I am like everyone else and would gladly (grinning & rubbing my palms together) take any free horsepower that could be found. I'm thinking if cowl induction REALLY worked, we might be seeing it on every single performance application out there. Response?
I have a '72 so I can't respond to a '76 body modification question, but there's nothing for you in this one. Your engine is already taking in cold air from ahead of the radiator. There's a difference for engines taking in air from the engine compartment, but, again, this wouldn't apply to you. If by your comment "...if cowl induction really worked..." you mean a ram-air effect, then the answer is no -at least not in this configuration.
The cowl induction benefit on C3s is primarily the provision of cool air (unheated by the radiator) to the carburetor. A slight hp increase, and a slight decrease in combustion detonation tendency. And pretty much every new car these days gets their induction air from outside the engine compartment for similar reasons. Pretty common thing.
When I restored my 73 the original hood was cracked. I found a hood from a 76 which did not have the mechanical assembly but did still have the duct built in. I cut three oval holes to allow fresh cowl air in but have no sealed air cleaner. So my expectation is that while it provides cooler air underhood at speed, that is the extent of the benefit. However they way it is cut out, fabbing up a NASCAR style air box would not be difficult.
Heres my solution. No numbers to back anything up, but I feel like I have a bit better throttle response and a bit more power from cranking up the timing. With that, she runs like complete crap in winter with temps below 45. Also you have a lot more cabin noise, but I kind like it.
Impressive, to say the least! Tired of working for a living? Pay the $5K for a Utility Patent and shop the prototype around or get it built right and sell to Eckler's, CC, Zip, Mid-Am, Full-Throttle, etc., etc. That is as good of a cowl plenum for the '76 as I could think up. Just a couple of questions:
1) Does you hood close properly?
2) Where did you get the parts? (I see the MATAC logo; I got that under my cockpit carpeting)
3) Does the car run any hotter/colder (temp gauge) since the snorkel front-ram air has been reversed to a full cowl induction?
Man, you ask a question and you definitely get an answer around here. Bravo, Guy.
1) Does you hood close properly? Yes, I attached a board under my Moroso air cleaner and used modelling clay to determine the height that I needed. Then I trimmed the air pan so it had a small clearance for the weather stripping to get a nice seal against the hood. The 76 hood has a cross bar with the cable for the hood release at the back so I used a softer foam to seal against it. It only pulls air out of the two holes I made in the rear of the hood now.
2) Where did you get the parts? It's been a long time (10+ years ago) and I don't remember where I got the "tray" that I attached to the bottom of the Moroso drop base air cleaner, but here is something similar made from aluminum. Mine was fiberglass and I had to modify it to fit over/around the HEI distributor.
3) Does the car run any hotter/colder (temp gauge) since the snorkel front-ram air has been reversed to a full cowl induction? Not noticeably, my engine didn't have any overheating problems before, nor did it afterwards.
Don't have any before and after numbers, but it runs fine and I didn't notice any huge engine noise differences.
That is Awesome!! I was looking to do just that on my car-nice job. Do you think one of those k n filter tops would give even more air flow? Especially since the rest of the system is enclosed? https://www.summitracing.com/parts/k...FVFbhgodSTsHuQ
07-26-2016, 01:26 PM
C3 Cowl Induction hood conversion (1976)
