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I have a 302 and I want to put my 400 heads on it. How hard is it? I understand I need a boss intake manifold, but that is not a problem. I have all the parts, so don't ask me why. (Just for fun really) I thought the only mod. was to block a water pass. here and open one up there??????
You got it. You need to plug the head coolant ports on the top corners of the deck face, where the coolant flows back into the block on a Cleveland, then drill new ones in the intake faces on one end of each to let the coolant flow to the intake passage. You'll need 7/16" head bolts long enough to thread into the block thru the heads too. Then Cleveland type pistons are needed that will work on 302 length rods, unless you have a set of Boss rods or 289 length rods to use with Boss 302 pistons.
Right, in case you haven't noticed, the Cleveland's valves are not in-line like a Windsor head. Thus the valve reliefs in the piston tops are also different.