I have done the swap and there is tons of bad info out there. They run fine just bolting them on with factory head gaskets, yes it is very high compression but these are not iron head 440s that ping on 9.5 compression. I did not need anything but intake manifold, exhaust manifolds and heads from the later engine.


Now if you put those early pistons in an eagle block they will come up above the deck instead of just below the deck like how they came from 03-08 and you will need to run thick head gaskets for quench clearance. The eagle has a slightly shorter deck height no matter what some clowns that don't know the facts will say... just because they saw it in a service manual or parts catalogue does not mean they are actually the same.


I have not done the swap on the jeeps you mention so I can't say about the headers. Most everything ive done is LX and trucks