Too bad you did not take advantage of the situation and degree and advance the .450"in.460" ex camshaft in this motor.
( If you were to degree it you would find it is retarded (115in/113ex C/L's) 114LSA (retarded by 1deg)
Moving the cam to a new 107in/121ex C/L position (7degree advanced) will wake it up and make more torque in this low cr engine. as the intake valve will close sooner.
This cam was GM's origional 1969 11:1 ccompression 350-350HP L-46 cam.
As installed it is a mis match @8.5:1cr. It need to be advanced.
If the new head gasket is thicker than the old stock head gasket the compression ratio wil now be even lower.
Should have wacked some off the heads (.050") and used a felpro shim head gasket.
I would have home ported the heads too.