My1974 Chevrolet 20 truck w454cu it runs rich. Original 33k miles on truck. The choke works ok after the warm up. But after driving for a 20 minutes I still see black rich exhaust FM tailpipe?

You need to have the carburetor rebuilt by someone that knows carburetors real good. There is 2 well plugs in the bottom of the fuel bowl that are leaking fuel stright into the intake. They need to be resealed, and not just anyone no's how to do that.

ARE you can just by another Carburetor. That is if you have a Quadrajet Carburetor.

If you have a HOLLY carb. on it then the Float level is to high or the Jets are to big and the POWER VALVE is probley leaking are blown. REBUILD CARB.