71 340 Compression Test

I had to run that little SB 350 at +10deg advanced on timing w/GM-HEI ignition but it worked really great.

Think I am going to have the little 340 rebuilt while I have it out for the paint guy. I like the warm/fuzzy feeling of knowing what I have from the start. Engine heads are 73 model indicating 1.88" intake valves, block and intake say 1971.
Would be awesome if the block has a forged crank but not holding my breath. Engine builder says he tries to stay between 400-450 hp on cast cranks. 400 is about where I wanted to be.
If I were to decide to put a forged 3.31" stroke forged crank in it, any of you guys know where a guy might pick one up?
Also thinking of trying to stay around 9.5-10:1 on Scr in hopes of being able to run the 91-93 octane fuel? May not be possible? Going to have the shop cut in 2.02" intakes on the heads. Any advice as to brand for valves "Manley" etc?