LA360 compression

If you know all the specs of your engine, ie pistons/compression head cc’s (which you already know) than you should be able to figure your compression, there are a few online calculators out there to give you a fairly accurate idea of what your 360 is capable of.
Summit has one I know of.
Unless your block and crank are pooched, it shouldn’t be overly expensive to build that block.
If you are looking to drag race then throw more money at it but if you just want to have fun on the street I think you have some healthy parts to start with.
The parts you have should be adequate to get you moving (not a dog) especially in a 360.
Not sure what KB’s you have but I cant see why those parts wont make that engine come to life in an A body!?

Do some homework on the piston part number to figure out what you have but I think KB pistons usually bring the compression up, from stock anyway.
My 360 pistons are about .025 below and it calculates out to around 9.1-9.4 comp.

A friend used that same cam in a stock 360 short block with 1.88” valves in a Valiant and that car moved!