Studebaker Carburetor Swap

[Stuhawk]

Will a Street Demon 625 cfm carb fit on a Studebaker late model (63-64) AFB intake manifold without using a spacer or modifying the intake ? I was able to find out that the primary bore on the Street Demon was 1 3/8" but couldn't find out what the secondary bore would equal if the Google valve was 2 circles instead of a Google valve.
Also what is the primary and secondary throttle bore sizes on a Carter AFB ?
Thanks in advance.
Stuhawk

[PackardV8]

No. The Street Demon uses the Holley bolt pattern.

jack vines

[Stuhawk]

Jack,
It's my understanding it has a dual bolt pattern a AFB and a Holley.

Stuhawk

[jrlemke]

Most AFB's have 1 1/2 bolt patterns (6 holes), just drill the two missing holes. Some Lincoln and Chrysler have eight holes.- Jim

[bensherb]

Yes. The "Street Demon" is a dual pattern and will fit both the Carter and Holley patterns. It will not fit the AFB air cleaner size, it fits the Holley 5 1/8" air cleaner base size. The primary throttle bore is 1.370", the secondary throttle bore is 1.747".

[Stuhawk]

Yes. The "Street Demon" is a dual pattern and will fit both the Carter and Holley patterns. It will not fit the AFB air cleaner size, it fits the Holley 5 1/8" air cleaner base size. The primary throttle bore is 1.370", the secondary throttle bore is 1.747".

bensherb,
Thank you ! That's the info I was looking for. Now I need to know what size the primary and secondary holes are in a late model Studebaker AFB intake manifold.

Stuhawk

[DEEPNHOCK]

Primary: 1.465" (+- .010")
Secindary: 1.715" (+- .015")

Measured on actual manifolds with digital calipers.

[Stuhawk]

Primary: 1.465" (+- .010")
Secindary: 1.715" (+- .015")

Measured on actual manifolds with digital calipers.

Jeff,
thanks, now were starting to get somewhere. I was just getting ready to contact you when you posted. I believe it might work as long as the actual venturi centers haven't changed. I checked into purchasing the base gasket for a Street Demon for comparison but it wouldn't help as it is the open plenum style. What would help is an AFB metal base gasket and place it on the Street Demon carb to check the venturi clearances. I also know that the AFB has a 4-1/4 x 5-5/8 bolt pattern and that the Street Demon also has the same on one of it's dual bolt configuration..........

Stuhawk

[Stuhawk]

As a side note for anyone interested.

Per bensherb the 625 cfm Street Demon has a primary venturi of 1.370" (1-3/8") and a secondary equivalent venturi dia. of (1.747") 1.75" rounded off.

The 750 cfm Street Demon has a primary venturi of 1.687" (1-11/16") and a secondary equivalent venturi dia. of 1.75" rounded off. They both have the same size goggle valve and the difference in cfm size is in the primaries.

Thought you might also want to know.

Stuhawk

[Bud]

A friend of mine just put a Demon carburetor on his Avanti engine and he said he had no mounting or linkage issues. Bud

[bensherb]

I run a 1" thick phenolic spacer under my AFB to keep the carb from heat soaking. With the junk they're calling gasoline these days the carb will boil dry within an hour of parking in the summer without it . A bonus is with the extra inch ANY carb linkage will easily fit.

[tsenecal]

Besides whether or not it bolts on, will 625 cfm be too much carb for a 289"?

[Stuhawk]

Bud, bensherb,
Thanks guys for the info. Good to know.

Stuhawk

[Stuhawk]

Besides whether or not it bolts on, will 625 cfm be too much carb for a 289"?

I'm not sure. It probably depends on the tuning and how you drive it. I guess it's like going from 195 hp to 225 hp by using a 4 bbl carb. Could it be the 2 bbl was as much undersized as the bigger 4 bbl was oversized.
Wasn't some of the AFBs installed on Studebaker motors bigger than 500 cfm.
Stuhawk

[Flashback]

I have one on my 53, with a R1. I had to trim bottom of linkage to clear. No problem. I would post a picture if someone would give me a step by step in plain English, on how. I have not been able to post since the photobucket change.