I have a new set of tfs 23 degree aluminum heads with 64cc chambers. I was wondering if anyone knew how much to mill these to get 58cc chambers? I have a internally stock 90 model l98 and would like to get 10 ,10.5 compression from it.
thanks in advance for your help.

 

Probably a couple hundred bucks. $250 maybe.

 

If your machinist can't give you the amount for this change off the top of his head---GET A NEW MACHINIST---
Actually this is something auto machinists deal with kinda frequently and they have the numbers--or if it is some weird never before seen head they can C.C. it--but usually small block heads are a standard daily procedure.

 

It's about .006" per cc.

Be sure you can get the required octane gas nessessary to
run 10.5:1 cr before ya do this.

10.5:1 cr on 92 octane is pushing it.

The way I figure it you could bolt on those heads at 64 cc
on your stock motor with a factory style .015" shim gasket
and get 10.28:1

Bore 4.00, stroke 3.48, deck clearance .025", flat top piston valve relief vol 5cc, .015" gasket vol 3.5cc head cc 64cc
If this turns out to be too much compression,
a .028" gasket will be 9.97:1

 

thanks for the replys. I didn't know there was a steel shim gasket on the L98 but I've used them before so thats okay. I thought with aluminum heads you wanted to run about 10.0-1 because of the heat lost compared to cast iron? If I can get 10 to 1 without milling my heads then thats great.