Anyone have any ideas on what would cause this and how to fix it? It's on a 383 SBC with a big solid roller cam. .630/630 and 274/284 at .050.

Any help is greatly appreciated!!

Probably the throttle blades are too far open. With that size cam you should have a four corner idle system. Try setting the initial advance higher. That will bring up the engine speed then use the idle speed screw to bring the idle back down. Make sure the primary and secondary blades are open about the same amount at idle. You might need to drill holes in the throttle plates. As is, the engine is pulling so much air through the boosters that they are dribbling.

Pat,

Thanks for the advice. We did try to open the back throttle plates a little but after doing so, the carb was still leaking fuel. We'll start with the timing and then drill holes in the rear throttle blades if we need to. We have the holes in the front throttle plates already.

I also like the 4 corner idle idea but I'd have to find a good used cheap carb. The guys I work with just won't spend the $$ on a new carb.

It's a friends truck so I'll let you know how we make out!!