I just did/in the process of a build just like this. It's for my daily driver & I did the 1.920 flat top forged pistons, XE274H comp cam, E-Street 75cc heads, 0.039 Fel Pro gasket, stock forged crank, stock '65 rods, ARP Rod bolts, ARP head studs, Stock Rockers, RPM intake.
It ran good, I put 45 miles on it & the block cracked along the water jacket. Replaced the '65 block with a '68 383 & on start up bent the intake valves while hitting the pistons & all the pushrods bent. Checked the block & it's been decked. Still need to check the timing chain to see if maybe I got it off.
I think it's going to be a good set- up with almost 10:1 compression and as soon as I get my heads back im going to check it much better, run a solid lifter & adjustable length pushrod to check my clearances.
Sounds like we both learned the hard way
With the Speed Pro 2315s and no valve reliefs , running the 75cc E Street Heads
Cam selection is pretty limited or tame