Back to basics which is the quality of the existing block, crank, and rods.
You said the block has been bored .030 which should indicate that it was cleaned and inspected for cracks before cash was spent on boring and honing. An unknown is the straightness of the main bearing saddles and the fit of the caps. Your machinist should have checked these things. If the mains aren't straight then the block should be run through the align hone process. The head deck needs to be inspected for flatness, waviness, and plane.
The crank also needs crack inspection and bearing journal surfaces inspected and repaired as necessary.
Rods, nothing like old rods you never know about them so they need to checked again for damage in the bearing bore caused by a loose or spun bearing, straightness and twist in the shank, and cracking. Rods are super important, one of these coming out and most if not all the thousands of dollars that went into all the other parts and processes is just gone to the scrap dealer.
The head deck dimension has a large effect of compression the Chevy standard is .025 inch above the piston. If it is at standard with a flat top piston and a gasket of .028 inch thickness and heads with a combustion chamber of 64 ccs then you're looking at a high compression of 10.0 to 1. This would favor a pretty radical cam. If the block is zero decked all other things being the same the compression becomes an even higher 10.6 to 1. By purchasing heads with 76 cc chambers these SCR ratios become 8.8 or 9.3 respectively. This shows that you need to think about the fuel octane you will use, it ties back to cam timing through the yet to be discussed Dynamic Compression Ratio (DCR) which is the result of finding the needed DCR compression ratio to compensate for stroke consumed to the point of intake valve closure. Since you have the bottom end kit with pistons the type they are is going to influence if not dictate the cylinder head combustion chamber volume and camshaft timing.
I know this looks simple going in and sometimes just buying parts and throwing them together works but more usually it's a lot of money spent on something undesirable. To avoid that requires a lot of planning and that involves experience and math. The Crankshaft Coalition found at this site has a lot of information and by coming here you stumbled into a site with a lot of experienced people giving away what is very costly information to obtain if you have to buy it.
So to start with tell us about the block and bottom end as I outlined much earlier. Once we know what were building on we can offer a lot of assistance that will build you a darn good if not great motor.