Holley guru's- need advice

If it were me. I'd put it back to box stock settings, jetting, PV, pump cams and squirters as a baseline. If you know your idle/cruise vacuum, you can make a better selection on a PV than what they come with. Probably not a big deal either way.

I'd run what Brian suggested. Brian built a 360 for a friend of mine, put a OOTB 4779dp on it. Car runs really well with no tuning other than idle mix and idle speed adjustments. Got 20 MPG on the highway with a 2.90-3.00 rear gear and 2500 hughes converter. Not bad for a car that ran almost 105 mph at MATS, 71 Demon. The carb was a smidge rich, so there was more in it!

The throttle plate holes can be filled with JB weld/epoxy.

If you want to sell the 750DP you have, I'd be interested.

Good luck with it.