i have a 78 351 w that's bored 40 over and has only been started a few times . will gt40 p heads work on it and what is needed to do that ?
I think the head bolts are bigger for the 351. Not a huge deal but I think the holes need to be drilled out to accept bigger head bolts or studs...7/16 verses 1/2 inch.
To put 351 heads on a 302 you have to use bushings in the heads or tap the block for 1/2 inch bolts or studs.
it did have dished ones in it but I put 69 flat top keith black ones in it .The only thing you have to be considerate of w/ the increased stroke of a 351 is the chamber size. What is the chamber size of the GT 40 head? In the history of the windsor's highest compression, a 69cc head yielded a CR of 10.7:1.
I'd imagine that a 78 windsor probably has a dished piston deep enough to eat cereal out of, so you'll want the smallest possible chamber you can get to yield a target CR of 9-9.5:1.