[Keithc8]

You have to find the problem before you start trying to fix it. Is the head gasket leaking, is the block leaking, does the head have a leak in one of the runners, has the sleeve dropped down and the head gasket not sealing and I have seen several intake gaskets leak into the end cylinders. I think they have added something to the anti-freeze in the last few years because we have seen some of it eat on the intake and head gaskets. You can do a leak down on the engine at the top and the bottom with the rockers of and you can pump up the radiator as mentioned before.
What block and heads are you using on your engine build? Good luck, Keith