"half of all carburator problems are located in the distributor"
I'm not positive where that came from, but it has proven to be great advice. It is quite a bit of work to unhook, unbolt, and disassemble a carb. Quite a bit less to make sure we have good spark at the proper time.
Timing can affect how well the carb works. Holleys have a transition circuit that is very sensitive to where the throttle blade is at idle. When the engine doesn't have enough vacumm, we open the throttle with the idle screw to get the idle speed we want, but that affects the idle transition port.
You need to hook up a vacuum gauge to manifold vacumm. There are two vacumm ports on the Holleys. One is ported, one straight manifold. The ported one will have the lowest vacumm at idle. When you identify it, plug it and forget it. Your jimmy distributor was always on manifold vacumm. Unhook the vacumm line to the dist and slowly advance it until you find your highest reading, then back the timing off until you've lost 2*. This is a good baseline setting. Hook the vacumm line back up and set your idle speed, and adjust the idle mixture using your vacumm gauge. Now, watching the squirters, rotate the throttle. They should start immediately. If not, adjust. Take it for a drive. If it is still bogging, you'll need a larger squirter. Holley makes them from mid 20s- mid thirties. The power valve enrichment circuit default is full rich. if the power valve is compromised it wouldn't be the problem here. Sorry for the long post
