Visit The Dirt Forum for More Information

Author Topic:   2bl Carb Tuning
Dirt Full Roller

Total posts: 66
posted July 07, 2001 02:13 PM
I have a good 2bl carb off a chevy truck, besides removing the choke what can I do to get the most performance out of this? *Anything Goes*

Dirt Full Roller

Total posts: 57
posted July 09, 2001 10:45 AM
Without writing an entire book here, there's lots of things that can be done in your situation. Assuming this is the 1 3/8" venturi carb you have (may be, may not) there is a good starting point.
Install Holley jets for ease of tuning first. (you'll need a 1/4"x32 tap). Next, a good amount of baseline info can be obtained in the book by Doug Roe called "Rochester Carburetors" (check
In your case, I assume that "anything goes" means you can modify your carb in any way you want, which you quickly will find that the only way to do this successfully is to have access to many specialty machining tools.
The typical "no rules" 2G carb will have at least a 1.75" throttle bore with special butterflies. The baseplate will be milled in a fashion so as to move the butterflies slightly closer to the venturis as well.
The venturi's are enlarged and offset-bored and totally reshaped for maximum airflow, as are the booster assemblies and air bleeds and power restrictions.
Fuel circuits are opened accordingly, reworked and customized as well.
Much of this info you will find in the book I mentioned above, but there are many other things that carb builders do not consider "public information". At least until I came along - I'm the sort of guy who if asked, I'll tell ya....just tryin' to help...and I hope this did.


Back to the Archives