Head shaving help

[circusracer]

Hey guys, I have an '89 corolla with the 4A carb motor, I am taking off the head and having it milled down to bump the compression ratio for some more power. My question is: what is the most I can take off the head safely before I have to worry about wacking a pistion? Thank you for any advice.

[toyomoho]

You can use clay to determine the exact clearances you have now. 0.040 is stated to be OK for most engines. A lot things effect compressing including having a valve job, which sinks them lower in the head and increases chamber volume.

A better way to go might be looking for a thinner gasket at performance websites. This will extend you heads life in case one day you remove it, find it is warped and it needs to be faced off again. Milling the head will increase compression but not that much.

[94_Rolla_Guy]

if you want a thinner gasket look at a 1993-1997 7A-FE head gasket there multi-layer steel and its like .023" thick i think it should work on the 4A-F compare the two.