Low compression readings can also come from a weak starting system. Are the cables new? Battery the biggest you can fit? I havent used a factory old-type starter in 10 years. The remans are terrible in most cases so I either get a used factory Magnum one or buy the brand new MP unit. You will not have to buy another one once you do that. I also think you need to verify TDC because it sounds like the balancer is junk. At least make a single mark over the inner ring, rubber, and outer ring and see if it's moving around at all after driving it hard. That cam should have another 5-8° at idle and idle speed should be down near 650. I think perhaps the lean burn Thermoquad carb needs some work too to run properly.