well... I finally got around to getting a new carb!

Decided to go with the speed demon 750 double pump.. running on top of a victor jr with rpm heads ( 383 bottom end )

Any thoughts on what kind of gains i will see over a 600 vaccuum secondary holley?

I looked at the specs and would *guess* about 30hp on the top end. I'm sure you'll feel an improvement throughout the rpms. Take the time to do some tuning on the new carb, most of the time there is much to be gained in performance and drivability.

when you put the foot to the matt you will know your money was well spent

Jinks,

The Speed Demon series carburetors are designed for a slightly smaller camshaft. Less than 240 degrees @ .050". If you have room to install a 4-hole carburetor spacer between the carburetor, and intake manifold you should be OK.

do you suggest i goto the mighty demon? I think i can still exchange it and go bigger smile.gif

It would be nice to have the option of a choke though...

What would the 4-hole carburetor spacer do for me?

The 4 hole would help produce torque.

Jinks,

A Mighty Demon would give you better top end performance. The 4-hole spacer will increase the air velocity going through the intake, which will help atomize the fuel better with a cam like you're running. It would also increase the torque, and throttle response.

BG Tech,

What Demon Carb would you recommend for my BB?

460BB @ 10:1
Solid Lunati 243/251@.050
TH400 with 10"BTE ~3200 stall
3.73 Posi

I was thinking the Mighty Demon 850 with annular boosters. Explain the difference between the annular and downleg boosters and what they mean to me a 90%street/10%drag car.

Is being without the choke on the street going to be a PITA? Notice that I do live in Florida.

Troy.

Troy,

Nice looking car. On your combination I’d go with the 850 Mighty Demon with the annular boosters. If you have room to install a 4-hole carburetor spacer between the carburetor, and intake I would do that also.

Annular vs. Downleg boosters. First off there is not a right or wrong, better or worse. It’s a matter of what is going to work best on the application. On the exact same engine with the same size & calibration of carburetor an annular booster carburetor is going to flow more fuel, give better atomization, and give better throttle response. It is also going to flow less air, and have the potential to go richer at wide-open throttle. Essentially an annular booster in the same size carburetor allows you run a carburetor that might be slightly larger than normally recommended to run on the engine. In your specific situation with the weight of the vehicle, type of gearing you’re running, and based upon your engine specifications a 750 is going to be too small, while a downleg booster 850 would probably be a little to big. Sort of like the gold-e-locks. Too big, too small, and just right… As far as a choke it is really a matter of personal preference. I do not run one on my personal vehicle, and it was 28 the other morning, and it started and runs just fine.

i ended up switching for the mighty demon.. thanks for the info smile.gif