Offenhauser and holley 390 orientation

[brianbronc]

Got the intake on.  Does the holley 390 have the electric choke facing firewall or fan?  Or facing the fender?

[Gary Lewis]

I don't know, but I'd think that the throttle linkage, and potentially the linkage to the transmission, would be the decision maker.

[85lebaront2]

First, if the manifold is the dual port style, the primaries should feed the smaller passages. Other than that, I always preferred the primaries outboard on an in-line engine.

We had a boy that worked for us at Preston Carburetion. He had a Chevy pickup with a 250 ci 6. He got a wild hair, bought a two 4 barrel intake and wanted some carburetors for it. I handed him two Stromberg 4 barrels from early 50s Buicks. They actually ran pretty good sideways on the engine.

[brianbronc]

Sorry.. it is the Offy Dual port intake

How to tell the smaller passages on the intake.  ??

[85lebaront2]

If you look at the head face of the intake, unless they have changed since I had one on my 260, the ports are roughly 1/3 - 2/3 with a divider across them. On the V8 ones the primary barrels connected to the smaller passages. Here is a picture of one with a Holley (unknown size) on it, note the primary barrels are outboard.

[brianbronc]

in that orientation... my throttle linkage hits the intake...

[85pig]

Are you using a spacer?

The Offy "C" intake runs the carb in the "standard" direction.  With it my linkage is fine with a 1" spacer; not sure if the linkage would drag the top of the intake without it.  Interesting info.

[brianbronc]

no spacer, but will get one and try

[85lebaront2]

That is probably because Holley decided a number of years ago to put "universal" (Chevrolet style) throttle levers on their carbs. The "Powerglide" tail hangs down in the way on an in-line engine.

[85pig]

It's not just Holley; just checked my Edelbrock AVS, and without a spacer, it drags a runner too - as well as possibly hits that manifold bolt.

[James191145]

The carb is oriented where electric choke is facing radiator and throttle lever towards firewall. This orientation is for the 6019DP manifold.

[85lebaront2]

Same thing, the "Powerglide tail". A spacer will solve it.

[85lebaront2]

The only question I would have is which side of the manifold feeds the larger portion of the intake ports?

[brianbronc]

previous in this post it was mentioned that the throttle linkage faces the radiator...?

[James191145]

On the c series , it is a single plane manifold. Doesnt matter which orientation on that one. The dual plane requires throttle toward firewall.