Closed Chamber VS Open Chamber BBC heads

[OBS454]

While the appeal of more compression is tempting I prefer the open chamber design for the flow characteristics. Do you have flat top pistons? That is very important too. Do you know what the cam profile is? I would check that first to see which would work better with your two options. Lots of info out there on potential combos so find out what you have first then make some decisions. Also, using a metal shim style head gasket can help with increasing compression slightly (re-torque after warm up is in order if memory serves). I run a carburetor and HEI and the heat my 454 makes causes pre-detonation if I put in too much timing (no computer/knock sensor) due to pump fuel. More compression would exacerbate this condition. If you have ECM controlling timing this would be less of an issue and more compression could be compensated for.