The Stovebolt Site Forums The Shop Area Engine Shop Fenton headers/Offenhauser manifold ?

I have the Offenhauser, am considering the headers, I have heard the Offy needs some modification to work with the Fentons, what needs to be changed, exactly?

The mounting flanges are different thickness. Just use a file to get them the same. Also when you put them on the engine you will need to grind a little off the bottom of the intake manifold. Mr. Offenhauser and Mr. Fenton probably didn't speak to one another very often.

There is enough alum. there to grind, just take a little off at a time.

I had to grind on the mounting flanges, but not on the bottom of the intake. You'll need to do a dry fit to see where you'll need to grind. I would advise eliminating the bolts and use studs instead. Also, take the 2 alignment dowells at the ends of the heads out and replace them with studs as well. That will hepl with aligning the exhaust and gets a bit more clamping force on them as well. You may also consider eliminating the factory mounting clamps, as they do not work very well with this mainifold combintions. I ended up making my own from 1/4" stainless after fighting leaks. I'll try to get some good pix of my setup posted tomorrow.

When I had this set up on my 1 ton, I had to grind the flanges, and a little off the intake. I used my secret weapon, the 4" angle grinder. For the aluminum, I just used an fibre sanding disk on the grinder. I had expected more drama, but it was an easy process. The worst part, was trying to hold everything up at once, and putting the bolts in. I never thought of using studs, as Bill suggested above. That's a good idea!

Same here, the grinding. Mr. Fenton didn't get along or speak to Mr. Edelbrock either. Thank goodness there was a lot of meat so that they could clear eachother.

Edelbrock/Fenton 1

Edelbrock/Fenton 2

Clamp the two manifolds together before attempting to install them. This should be a lot easier.