Does anybody know what size main jet should be in a Rochester Model B carburetor on a 292ci? If anybody has a factory service manual for a '64-'67 Chevy Truck would you mind looking this up for me? I have a 1970 chassis service manual and it shows the later(M series) carburetor. My truck is running rich so I'd like to find out what the factory specs call for. Thanks in advance!

Andrew

The big 292 "B" carbs I have all have come with about a #72 Jet in them.

This carb is a lot like 1 primary barrel of a Holley 850 Carb, not the most responsive setup, huge venturi and throttle bore limited to 1.75" so I think the jet is kinda generous to give decent throttle response.

If you want to give up 5-7hp at the top end you can run a smaller car 1-bbl "BC" or "BV" carb, 1.25" venturi and about a #59 or so jet, a lot more responsive down low.

The carburetor came off of a 230, and I wasn't aware there were different venturi sizes, so I'd be willing to bet its the smaller 1.25" venturi. I drilled the original jet, and I believe its #72 right now which could explain why its running rich. I'll have to find a #59 jet and see if that helps. Thanks for the info!