Spent the day talking to several other guys about my problem and they seemed to think it was the accelerator pump or to try using a bigger discharge nozzle, since the one on the 4160 is smaller than what would have been on the stock carb. (Much as you suggested Zoo Keeper) I'll post back after these two things get checked out. If I get a larger nozzle, how much bigger should I go? The 4160 has a .031 should I pick the size the original 750cfm carb would had?
Ok, I'm going to give you the benefit of a doubt. Maybe, the video sound is misleading on the severity of the noise. You are the only one on this forum who has actually heard it in real life, so let's just say it is a pop caused by a super lean carb. It could either be a vacuum leak or a lean accel pump causing the pop. You need to make sure it is NOT a vacuum leak before you start tuning it. To do that, try hooking up a hand-held vacuum gauge to a manifold vacuum port. If your car has a stock or mild cam, you should see a steady reading at idle. The idle should not fluctuate, nor should the gauge reading. If you get a fluctuating needle, or the car will not idle on it's own, then replace either the base gasket or the manifold gasket or both to fix the vacuum leak. Once the engine has a good idle, and a steady vacuum reading, you can start to tune the carb. First make sure the accel pump circuit is working as it should, regardless of a small pump shot. Witht he engine not running, and the air cleaner off, look down in the carb and work the throttle by hand, and you need to see a shot of gas coming from each squirter. If you do not, then replace the accel pump umbrella and spring and clean all the passages in the metering block, as well as blow out the squirter nozzle. Then recheck it for an accel pump discharge (once the carb bowls have gas in them again). If you now have gas where you didn't before, drive the car again and evaluate any change.
If the carb still pops, it's time to start tuning. You can either tune the nozzles or the cams or both, but only make one change at a time. I'd start by making sure the linkage is tight on the cam. The cam is located on the throttle shaft near the throttle linkage, and all Holleys have two positions. They are marked "1" and "2". If the screw is in the "1" location, remove it, move the cam slightly until the "2" hole lines up, reinstall the screw, then test drive. You can also swap different cams altogether, and your local parts guy or Summit can help you pick a larger accel pump cam. If you want to swap squirters, then first note the squirter you have by removing it, then noting the number on the side. If I remember right, they are numbered from (I think) 25 to 51. The smaller numbers give the longest shot of gas time-wise, but the smallest amount. Going to a larger number increases the actual amount of gas, but decreases the time of the shot. If it's too lean, go up 2 to 3 sizes and then test drive. If you are doing this on the car, be very careful since there's a tiny washer under the squirter, and dropping it into the motor will make you say lots of bad words. Also, don't rule out timing, check your timing curve before you start to ensure your initial timing is right, and to make sure the advance is working correctly. Hope this helps. Jim
