I will be swapping in new heads very shortly. My problem is this. I purchase Dart Pro1 heads with 72cc combustion chambers, the biggest they had. I want to decrease my compression ratio to under 9.0:1 because I will be running a procharger. Can I have a machine shop port out the chambers or are there thicker head gaskets available that will reduce compression ratio? Anyone have a calculater or gasket thickness to get ratio to desired amount? It is a stock 5.7L in a 1988 GTA.

 

sure you can clean up the chanbers a little and that'll increase CCs to decrease compression. the "normal" fel pro replacement gasket is .041 i tihnk, don't know of any thicker

 

Actually, the Fel-Pro 1044 is about .010" thicker...

but with the L98 short block, 72cc heads should give you about 8.8:1 or thereabouts, with the regular .041" gasket.

 

And a head gasket is not a good way to decrease compression, since the stresses on the gasket increase with an increase in thickness. Much over 0.050" and you should consider 'O' rings.

 

8.8:1 sounds good to me. I was told the L-98 came stock with 74cc heads and 9.3:1 compression?

 

Stock is 9.3:1 with 64cc chambers.

 

Thanks five seven maybe they did say 64 and I heard 74.:hail: