Help with QF HR-750

Street car or not, the cam will be a bigger factor in initial timing than anything else. It's not stock so throw all the normal thinking out the window.

My 508 cammed 340 is locked out at 36*. Mini starters handle that easily. Older ones can have some cranking issues with the weak wire sizing.

IMO, no way will that run well with less than 20* initial, unless it's a 12.5:1 compression engine. Most I've fixed are in the 24+ range.

Before you spend one penny on power valves, buy a one or a pair of power valve plugs. Put them in the blocks as necessary and get the idle right. It will take that entire circuit out of play, still rich, it's not the PV's.... Then you can grab a vacuum reading and make a guess at what PV to use. I have a car that pull around 8" at idle with a 10.5 power valve, idles fine. Just don't drive the car around without the PV's!