Which carb, 4bbl or 2 bbl?

[spray004]

I recently bought a street stock. The rules where I race at say I have to use either a 500 2bbl or 600 4bbl with vac secondaries. The engine is 383, I currently dont know what size the cam is nor the compression. I'm going to try to get ahold of the engine builder and find out the specs of the cam. Which carb is better? I run on a 1/3 mile track that is semi high banked. The current intake is a marine intake but I plan on swapping it out with a Victor or Victor Jr.

[newguy]

I have no experience with a vacum secondary carb on a circle track, but i see that "slick track" carbs are vacum secondary, I would give a shop like willys a call and see what they think, they will probably need your engine info, and kind of track in order to give you good info, that being said, i was more than impressed with the performance from my VDL 4412.

[DaveBauerSS6]

Go with the 600. More power. Get the quick change vac housing made by Holley. Get the assortment of vac springs and tune the opening rate with the springs. When you get used to it, you will end up with a slick track and a hooked up track pair of springs. A couple minutes to change. If the rules allow it, get the secondary metering block conversion and you can tune with the replaceable jets.
Good luck.

[spray004]

The rules are vague. They simply say 500 cfm 2 barrel or 600 4 barrel with vac secondaries. It says nothing about modifying them. I was looking at an SMI Carb, he's the only one I've found to date that modifies 600's with VS.

[te33]

I have a KP built Holley 1850,well worth the money.

[sj valley dave]

SMI is very good with carbs..he does tons of drag racing, boats and circle track..Don't forget that a 500 cfm 2 bbl is rated at 3" of vacuum..a 600 cfm 4 bbl is rated at 1 1/2 " of vacuum...tested with the same vacuum, the 4412 will only pull approx 375 cfm..I agree with Dave Bauer..a 600 VS will make tons of more power than a 4412...

[dirty white boy]

more cfm = more air= more power can be made!

[500BOMBER]

600 carb...................YYeuuuuppppp!