I'm posting here to avoid the fist fighting in your other post...lol. Sorry to highjack. But really, any engine needs to be asembled and parts chosen properly. See how many 289 Mustangs get 302s in them. There are some, but original only means one way. The 273 can run great too, especially in these light cars.
My feeling about poor hot starting is that the compression was low. That isnt caused just by the lower compression pistons or head gaskets. What you are testing is the amount opf pressure the cylinder builds on a typical compression stroke, as it is currently assembled. That last bit is the real meat here. The cam timing and size are what really makes it or breaks it. Whne the engine is cold, the fuel will stay in liquid form easier. It gets more into the cylinder easier, and it fires right off. Leaner mixes are harder to fire. That's why I'd bet if yours wont restart easy, you need to pump the gas a few times while it's turniong over and it will. Your readings with a fairly middle of the road cam should be in teh 140-160psi range with a low static ratio piston and the cam I seem to recall you having. It's low because the cam wasnt degreed, and it's in wrong. I've fixed several egnien for fellows who never knew the engine had isues until I drove it and told them. IN every case, the timing set or the cam was an issue. I one case, a 383, it showed 120psi in all 8 after being warmed up. I took the front off, and found the timing chain off one tooth (retarding the cam), and the cam itself (the MP 383HP resto cam) off 6 degrees (again retarded). After repair, the same engine warmed up had 175psi. It went from not spinning the tires w/3.23s in an 68 RR, to not stopping spinning the tires until 2nd gear. You need to find out if that's the case. It's definately low. way low even for a low compression engine.