[patrickt]

Replace the pump and see if all the problems magically go away. Check your fuel pressure -- something in the sixes is about as high as you can live with. If the richness problem is still there, order the Holley “Fast Kit” #37-1542 which has all of the gaskets, and other rebuilding parts, for the model 4160. When it comes, two of the needle and seats look like they are an exact match. One will be .110 and the other is .097 -- the instruction sheet will tell you that the .110 is the correct match for a needle and seat marked with an “H” on it (which is what you likely have). And put a dab of Vaseline on the black O-ring, that makes the needle/seat valve slip in to the bowl easier. Change the PV even if you think the one you've got is good. Set the float level “dry” so that, when inverted, the brass float is parallel to the bottom of the fuel bowl. IGNORE THE INSTRUCTIONS THAT SAY TO SET THE FUEL LEVEL TO THE BOTTOM OF THE SITE HOLE. With today's gas, and if your engine and carb tilts, you have to set it lower than that. Just set it as high as you can get it, and after each hot run pull the air filter off and see if you're dribbling out the boosters. Turn the floats down a hair at a time until the drips are gone, or pretty much gone. Then, if you are still experiencing richness issues, it is likely the "hot idle blues." There's an easy fix to that and we can walk you through it. But the first step in making a 4160 a wonderful carb is getting the parts not leaking and getting the floats set right. When tweaked properly, a 4160 is absolutely spectacular. Again, IGNORE THE INSTRUCTIONS THAT SAY TO SET THE FUEL LEVEL TO THE BOTTOM OF THE SITE HOLE. Just shoot to get it as close to that as possible without dribbling.