Well if it does need a converter I would go with a 3,000 to 3,800 stall but it all depends on your engine combo. I use to run a mild 351w with a 3,500 stall and my car weighs 3,000 without driver.

Quote Originally Posted by iceburgh View Post
Just installed a 383 from a 350 crate motor.
The truck weighs 2900 using a 670CFM whne the truck is in park it will idle at 1000 rpm....once I drop it in gear it wll drop to 400 rpm then stall out.
I assume I need a bigger converter but do I need 2000 or should I go higher.
Run on the street most of the time