Has anyone done porting on heads, including moderate to extensive work on the chambers, and found the difference in chamber volume after the work? Any data at all would be useful. Im trying to get a feel for how much material will be removed from the chamber in the normal cleanup/porting process.

Reason for this:
I've got a decent deal on a set of TF twisted wegde G2's with 67cc chambers. Put that together with a .051 head gasket in my motor and that gives 9.14:1 compression. Ideally I'd like to be right around 8.5-8.75:1 (this is a 12-15psi turbo motor, fyi). Im on a tight budget, got a smoking deal on the forged pistons I'm using to assemble this engine, and i will not be changing them. They are flat top with 6cc valve reliefs.

I KNOW the right way to do this is get dished pistons (-24cc or so), small-ish chamber heads, and a headgasket around .025-.030 to maintain good quench. *This is a compromise.* I'm going to do some cleanup grinding and polishing on the chambers (in the proper way, not ONLY to increase chamber vol.). and i'm thinking probably 1-2cc is average, maybe 3-4cc removing a LOT of material.

Anyone?

 

Remove material and CC each chamber. Get them all where you want them and you are good to go. Ideally dished pistons would be better, though.

 

I was able to get a 2 bolt, fully prepped block, steel crank, forged rods w/arp bolts, forged pistons (assembled w/ rods & rings), main studs/straps, and some various extras for under $1000. I wouldnt be doing this if it wasnt that cheap. Another $500 for pistons? No thanks!

I'll probably end up doing that. Start out small, check cc, grind a little more, check cc, unshroud valves a tad, check cc. . . . .you get the idea. I'll probably aim for 3-4 total. Just wanted to see if anyone had measured this before.