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Holley 750 with annular boosters?

Posted By: dogdays

Holley 750 with annular boosters? - 10/18/19 06:36 AM

Scouting for used Holleys I ran on a Model 4150 double pump 750 with annular boosters in all four holes. It looks like someone took off the center hung fuel bowls and substituted two side hung front bowls, and the choke horn has been milled off. The size is based on a visual of the throttle plate. What could it be? I know it's a Frankencarb but it's a lot of work to swap boosters so I think they're original. I think the main body might be interesting. We have a couple of carb experts here, any guesses?

Thanks, R.
Posted By: Jeremiah

Re: Holley 750 with annular boosters? - 10/18/19 07:34 AM

The list number might be on it if it started life as a HP main body. Most of the annular carbs with 1 9/16 throttle blades were 830's. Side hung floats is strange to me unless its a really old carb or from a 2x4 app. I am no expert just a tinkerer and collector of carbs.
Posted By: GTX MATT

Re: Holley 750 with annular boosters? - 10/18/19 01:20 PM

Holley makes one, the 9379 Competition Series.

The 9380 is the annual 850, and the 9381 is the annual 830. The competition series come with choke horns in place, but no actual choke. If its annular but does not have adjustable air bleeds its probably a good bet its the old Competition series (which you can still buy new).
Posted By: Bad340fish

Re: Holley 750 with annular boosters? - 10/18/19 01:28 PM

I ran a 830 with annular boosters for years on an old a 475HP street 360 and it worked very well.
Posted By: Cab_Burge

Re: Holley 750 with annular boosters? - 10/18/19 05:07 PM

The early annular 830 CFM Holley had issues controlling the AFR above 5000 RPM, the higher you revved the motor the fatter the AFR went shruggy I think I heard the same on the 750,
maybe not shruggy
I have set of 1000 HP 4150 annular that I'm probably going to have Dominic change to down leg booster to run on one of my motors with a tunnel ram.
Posted By: dogdays

Re: Holley 750 with annular boosters? - 10/19/19 08:49 AM

Thanks everyone! 830 or 750! Interesting. I'm sure the fuel bowls were switched out to the less desirable side hung style because they're both primary bowls. Frankencarb!
I had read that about annular boosters going fat at high airflow. I'm going to try to buy it and see what it is. I'm the home for wayward carbs, most worthless.
R.
Posted By: dogdays

Re: Holley 750 with annular boosters? - 10/19/19 09:08 AM

i'm guessing it's a 4788.

R.
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