I have inherited (a long story...think teenager)a 1992 F250 4x4 that has had the original motor replaced. The truck now has the 460 block with 71' 429 heads, with the EFI. The truck has run with this combination, but it never has run right.
I guess my question is that are these 429 heads compatible with the EFI...or should I start looking for a pair of EFI460 heads.
Any help would be appreciated
Thanks

 

The heads are fine, it's the efi intake manifold that doesn't fit. You'll need efi heads.

 

Thanks for the info. What is it that is different about the heads and manifold that make them incompatible????

 

The old heads have bigger ports that are lower than efi intake. They can be made to match up but you have take off material on the top of the ports on the heads and add material to the bottom of the intake. Otherwise you get a leak into the valley of the engine.

 

Besides the mismatch of intake ports the 429 heads have small combustion chambers...you'll have to start burning premium fuel to keep from knocking. Also the exhaust port shapes are different and your 1992 exhasut manifolds will no longer fit. Deen