Carb choice

[orangecrush]

What would be most recommended for a 340 4-speed car. Will have the Comp 268 cam (unless other is suggested) and 3.55 rear - why double-pumper over vacuum (if recommended) ? Thanks. I have a 670 Avenger (vacuum) that I can use - but not sure if that's what I want on a 4-speed car. I'd like to have a high 12 sec car but not sure if doeable(sp?) with the 3.55.

 

[rumblefish360]

It's do-able w/3.55's. But a stronger engine may be needed or a change up in gear/ suspension.

A double pumper works a little better on a 4spd manual car when your gettin on it and looking for any advantages possible. Theres also a long list of what is also good and has advantages over stock or what can be done to mod stock equipment. How far you go is a choice you have to make.

The DP, once you learn it well, has a minor advantage over a VS carb. But once rolling, it's really nice because you can just run the car/engine really hard and it responds well.

I'd look at a 750 DP and a cam change since that cam is smaller than a stock 340 cam.

 

[rebeldart]

I'd like to see opinions as well as I'm starting a 4-speed project next.

 

[Robzilla]

I'd go with a 650 DP on a 340. I am running a 650 BG claw on my 340 4 spd Duster with the MP .474 cam and 3.91's, works awesome, just rips the hides off!!

 

[crackedback]

which 268 cam?

Is it the XE268H or the 268H

I'd run a DP on it if it was mine.

 

[2 Darts]

Most sources I've seen recommend an air valve secondary with an automatic transmission and a mechanical secondary with a manual transmission. I have a 625 cfm AFB, moderate cam, on an automatic Demon w/3.55:1 rear. It works well enough to suit me.

 

[goldduster318]

I have a vacuum secondary carb on a 4-speed and to be honest, it never seems "flat" around a gear change. Buy a rev limiter and shift more aggressively (never lift) and vacuum vs mechanical secondaries will likely not matter.