Gary, I've looked everywhere I can think of and can't find the answer to my question. I have a set of the Signature series aluminum heads (rovals) that I plan to use on my newest project engine. It's a 4.600 bore/3.766 stroke crank 500 cubic inch engine for a hot street car. I'm very attracted to the short stroke for lowering bottom end torque a bit and the rev-ability it provides. I have a set of JE flat top pistons for this combo and want to use these heads, but compression ratio comes out to just a shade over 9:1. I'd like it closer to 10:1. These heads are listed as having either 110cc or 112cc combustion chambers. How much can I safely mill them, both flat and angle? I think I need chambers in the 103cc range for high 9's compression. Nobody makes a shelf piston for this application, even though my pin height is common with the 6.660 rods I'll be using. I don't care to have to use a domed piston with a head that's basically designed for use with flat tops. Of course, if anyone can provide proof that this point of compression won't be worth enough power to go thru the trouble, I'm not married to the notion of having to cut these heads. Any help anyone could provide would be very much appreciated.

Monday ttt

I just went through this too, it was either low compression pistons, or high compression pistons. I couldn't find any in-betweens. I'd like to hear what Gary has to say, too...I ended up with the domed, 12.7:1 SRP's, but then I won't be out on the street too much.

Food for thought...check with avengerclyinderheads.com They claim cnc ported Edelbrock heads with flow near 400 cfm. Also there is 100 cc Edelbrock heads availible.

To be honest if it were my motor I would be looking at a set of AFR or others. The GM heads are decent at best, especially for a 500 in. screamer.

I read your post too quick..you already have the heads, perhaps a good port job. I angle milled mine down to 105 cc (from 110) after being ported

There is plenty of deck on those heads to mill to your desired 103cc chamber. The official answer is 0.100, the Gary answer is much more, especially if you angle mill them. A mild bowl blend and exhaust port wouldn't hurt either.

Gary

Mill them down to 90 cc's and get the compression you want with flat-tops...

BUT I don't know how much hassle will be stirred up b/c of intake manifold and pushrod fitment issues..

(I figure that is Gary's much more answer??)....

pdq67