Offenhauser Intake Part Numbers

[WE2Regal]

Don't remember where I got this, but it might help someone if they are unsure which Offenhauser intake manifold fits their engine.

 

[ek02]

Interesting. I didn't know Offy made an open plenum for a 79 up even fire. I had an Offy Dual Port, then a Holly open plenum on an odd fire. I've had Weiand and Kenne Bell intakes on my even fires.

 

[WE2Regal]

I have 2 of the 6228-C manifolds. They are very different compared to the Kenne Bell and Weiand manifolds. The 6228-C looks a lot like the 6171-C pictured above. Notice the raised floor in the center and no EGR provision. Carb mounting pad is low and would easily fit under any hood. The ports inside look small compared to the Kenne Bell and Weiand though. Maybe that's a good thing?

 

[WE2Regal]

Here are some of the intake manifolds that fit 79 up high port heads. Top row L to R: Buick 4.1 25512236, Edelbrock Performer 5486, Weiand Smokey Yunick street manifold 7541 Bottom row L to R: Offenhauser 6228-C, Kenne Bell Number 1, Weiand Smokey Yunick race manifold 7542

 

[~JM~]

Had an Offy Dual-Port on my Dauntless 225 powered CJ-5.

 

[WE2Regal]

This photo from the original instruction sheet is the only photo I've seen that has all 3 carb tops for the Weiand 7541 street intake.

 

[WE2Regal]

Last one. Looking inside the Offy 6228-C.

 

[ek02]

That one looks a lot like the Holly for the odd fire in the plenum. The ports on the Kenne Bell intakes were smaller than the ports in the head to help prevent reversion. The manifolds were designed for stock engines as well as modified. I ran them like that on my old 3.8 even fire. When I went to ported irons and then to GN1 heads on my 4.1 stroker motors, I opened up the passages and matched the ports to the heads. The power band is strong from bottom to top. There does not seem to be any reversion going on. I still have one unported Kenne Bell. If you ever want to sell the Smokey Yunick 7542, let me know. I like the air gap design. Thanks for sharing.

 

[WE2Regal]

Couple of things I noticed about the Weiand 7542 . It does not have a provision for a water pump bypass and there are no bosses for mounting a factory style throttle bracket. You have to use a throttle bracket that attaches to the back of the carburetor mounting bolts and block off the bypass in the water pump. I saw this one on Craigslist advertised as a Chevy V6 Smokey Yunick intake manifold. I called and asked for the part number on the back of the intake. When he said 7542, I said I'd be right over.

 

[WE2Regal]

I guess I should probably throw this one out there as well. There is no doubt that the Holley Street Dominator 300-22 was originally designed to fit 75-77 low port heads. It was later marketed to fit both low and high port heads. Was there a running design change that made it into a "middle design" like some of the others? I don't know. But I placed a Felpro 1200 intake gasket on the one I have and it was certainly made for low port heads and not a middle design for low and high port heads. However, there is no reason it wouldn't fit the high port heads and there is plenty of "meat" to grind the top of the runners to match high port heads. Mine also has the firing order 165432 cast into it.

 

[WE2Regal]

 

[ek02]

I had that one on my odd fire. Used a 390 cfm Holley, then a 550, then a Quadrajet. The Q Jet ran the best. I have an Edelbrock 650 on the 4.1 with the ported Kenne Bell. Zero bog, right out of the box the jetting was perfect.