I'm starting up a fresh 64 427 FE and can't get past short run and blowing past radiator cap relief. Any ideas on possible assembly error?? Are head gaskets a possibility? Any help will be appreciated. Thanks
Yep, good possibility, I think you should see a tab of the gasket sticking out at the front of the head. (if memory serves me right) Maybe someone here can confirm this. That was one of the ways to tell back then.
Theres a few possibilities and the headgaskets are one.
First off is it actually getting hot and overheating or is it just pressurising in the cooling system.
Make sure radiator cap is good and not faulty. If it is overheating then you need to be sure the thermostat is working correctly and that the radiator is clean. If all these check out then if you can put a pressure gauge on the radiator then start the vehicle and see if there is a fast increase in pressure which would suggest compression enter the cooling system. You could do a cylinder leakdown test as another way of checking which bank is the problem.