1968 Pontiac GTO

DeuceCoupe · 09-26-2021, 01:26 PM

Stan,
Thanks for that - I had looked in your database (which I use a lot) already, but arent those the 1971 #96 heads, ie casting 481196, 96cc stock?

The RA2 #96 are casting 9793596, 71-72cc stock, those are the ones I can't find. I'd GUESS the exhausts are close to the RA4 heads but can't find any numbers.

For sure on the "Ram Air" - I find about a 4% plus-up just for the cooler air works well, if it's a good system- just as those smogger IMCO Snorkel things can heat the air up a little, even when the flapper is open. The late-60s-up IMCO snorkels cost about 2% power from testing I've done.

And of course the "ram" effect, if any, depends on where & which direction the scoops are. The Cobra Jet shakers look totally cool (got my 1st one at a swap meet for $20) but dont get much ram, if any. I suspect the grille and cowl systems have a little edge there, even for "sensible" speeds like 100mph or so.

Thanks again for your head flow database it does the community a great service.

09-26-2021, 01:26 PM	#26
DeuceCoupe Member Join Date: Feb 2016 Posts: 274 Likes: 98 Liked 48 Times in 44 Posts	Re: 1968 Pontiac GTO Stan, Thanks for that - I had looked in your database (which I use a lot) already, but arent those the 1971 #96 heads, ie casting 481196, 96cc stock? The RA2 #96 are casting 9793596, 71-72cc stock, those are the ones I can't find. I'd GUESS the exhausts are close to the RA4 heads but can't find any numbers. For sure on the "Ram Air" - I find about a 4% plus-up just for the cooler air works well, if it's a good system- just as those smogger IMCO Snorkel things can heat the air up a little, even when the flapper is open. The late-60s-up IMCO snorkels cost about 2% power from testing I've done. And of course the "ram" effect, if any, depends on where & which direction the scoops are. The Cobra Jet shakers look totally cool (got my 1st one at a swap meet for $20) but dont get much ram, if any. I suspect the grille and cowl systems have a little edge there, even for "sensible" speeds like 100mph or so. Thanks again for your head flow database it does the community a great service.