Open the combustion chamber?

I'm currently building a blower motor for my T/A and had planned on using the stock unported heads. They have however been milled and had a 3-angle valve job. One of the previous owners noticed a blown HG and had the heads trued while they were off.

With my stock bore(I was able to keep in my new motor), -18 or -20cc dish with a stock 9.025 deck height and a Felpro 1074 gasket gives me a c/r of about ~9.4:1 and a quench of .064. The blower is pullied for 12psi(ATI P600B). That compression seems a bit high to me and I'd like to lower it back to about 9 or less.

I've heard that it's not the best thing to do to open the combustion chambers up as it messes with the velocity of the incoming air. But how is that affected on a FI motor? If I could get my cc's opened to like 62 or 64 that'd be great.

Any help would be greatly appreciated.

Wade

Port design tends to take a backseat to port volume in FI applications to a point, and opening up the chambers can be done but not much. The LT1 castings are fairly thin in several places. Lloyd told me he could probably get them to about 58 or 59 cc's without any detrimental side effects, a local head porter told me he could get them to 64 cc no problem. I tend to side with Lloyd on things like this because of his extensive experience with the LT1 castings. So to sum it up, you could probably get them to 58 CCs without problem, and 64 CCs may be possible but unlikely. Send an e-mail to Lloyd Elliott ( www.eportworks.com ). He has always been very helpful when I contacted him.

I have done many 64-65cc setups & they work well. This is not unrealistic if you have not milled them too far already. Properly done, they also improve the burn pattern on the piston.

As far a 9.4:1 & 12#, this is entirely possible on pump fuel as well. By the time you add a cam, the boost will be drop under 12# anyway, so this is very safe if tuned properly.