I have a 78 nova with a mild smallblock in it. It has a 3core rad.
What rad cap psi is everyone running.

thanks rs78

i run a 14 psi.. just my prefrence for my 78 nova with a sb 350 and this cap werks great.:beers:



wiggy78

14-16 lbs should be just fine. Are you having issues?

I run 23 psi with no heater. I have an aluminum radiator that can stand that kind of pressure, but it would probably open a seam on a brass copper stock style radiator or the same brass and copper heater core. Higher pressure combats hot spots (steam bubbles) from forming in your block which is a consideration with a Siamesed bore BBC or a stock SBC 400 block.

Big Dave

I run a 20psi raidator cap, with a sealed over flow tank with a .5 psi cap and standard over flow tube.