Hi all, Im looking into buildin an ls1 iron block from my spare 5.3 I have sitting in my garage which was being used for mock up to put a lsx in my 94 firebird
v6 car, Im more on a budget for this build cause money is pretty tight with having 3 kids and the only one working, but I done enough side work to keep buying the cheaper parts I need. The plan for the motor is to keep it around 9.5cr cause I would like to run a procharger down the road but keep it streetable until than. Here is what I got so far.

Ls1 intake, Injectors
Ls1 cam stock
aluim fuel rail
stock 5.3 block which will be bored over for ls1 pistons
stock 5.3 crank
rwhp goal 450
Im planning to hunt down some used ls1 pistons and rod and have the crank and rods all balanced. Now I have a set of 5.3 heads and a set of 317 heads and I know the 317 heads would be good for boost and lower my compression but I have no idea what the compression would be cause I dont want it too low and same for the 5.3 heads No idea what compression Ill be running, I have searched for for anwers but I cant seem to find the anwer im looking for. and ls1 heads are out of the question cause shipping would be pretty crazy for a set if found cheap. The cam will be upgraded once I have a procharge in my hands But the mean time The stock ls1 cam will do.

now with me going to boost should I just spend the money on a new set heads or work with the ones I have now?