racinbird

Im looking to install a water relief passage from the back two cylinders off of the intake manifold. Its an edelbrock RPM airgap on a 502, I belive it has 1/4" ports already factory drilled. I know this will allow the hot water and steam to escape and keep heat from building up, but will this also lower water pressure? I had to rebuild the heads last year from no8 losing compression due to over heating. poor valve job/seat , cheapo valves and no relief. I am just planing on running this straight out the transom just under the swim platform, its a baja 232. any advice or comments?