I recently bought an 89 f150 w/ a 300 inline 6. The factory EFI system is a mess and I'm seriously thinking about converting it to an offenhauser intake manifold w/ 4bbl carb or tbi fuel injection.

Is my head compatible with the offenhauser intake?

Has anyone done this conversion? I searched the forum and see a few people running the offenhauser intake. Suggestions are appreciated... thanks

 

Head is compatible w/ the Offy intake - bolts right up. Dozens of folks have gone this way. IMHO more cost effective than a TBI reconfigure.

 

That's good news on head compatibility. Thank you

 

The only issue you may run into is your exhaust manifolds getting in the way of the Offenhauser intake. I've had two Offenhausers, and when I installed both of them for the first time, along with the exhaust manifolds from an EFI era engine, one of the hanging loops always gets in the way and I have to grind it off.

The EFI head has 16 bolt holes as opposed to 13 of the carb'd head. The 3 extra are simply to hang the manifolds from during installation (which is why they're a full loop instead of just a tab) so removing one of them won't hurt anything.

I also usually have to grind down a few spots on one of the runners in the exhaust manifold for clearance, or else it keeps the intake from fully seating against the head (instant recipe for snapped tabs).


Either way, it's easy to do, and about 5 minutes with a good grinder. Just make sure both the exhaust manifolds and the Offenhauser will sit flush against the head without a gasket before installing. If not, find out what's binding and remove it.

 

The extra fasteners were added to insure the exhaust manifolds did not shift downward during use. Since they do not bolt directly to the [EFI] intake manifold and since they are of two-piece design there is a possibility that they will migrate south over time. That is why I use retainer clips on them when using them on an early head.

 

Interesting, I've never heard this before (or noticed this trend.) I would think that the pipe underneath would be enough to hold them in place, or at least discourage them from moving.

What are these retainer clips?

 

retainer clips - right angle washers that grab the lower side of the mounting lugs

 

Thanks for the info.