One thing that I've found with Rochester "B" carb kits is that the seat that comes with the kit is drilled but not chamfered. The original has a chamfer in the hole that the needle fits. I take one of the old check balls out of the carb, and drop it onto the new seat, then tap it lightly with a punch and hammer. This puts a chamfer into the brass and seems to keep the needle from sticking. I have been on the same rebuild for 4 years on the "B" on my 261 with no sticking or flooding. Before that it would stick and flood every other time I drove it.
