79 pace car engine

[BLOCKER]

I am thinking of taking on some what of a project/resto. I want to build a 79 pace car but have some "perfomance" mods to it....
Here is what I am thinking for the engine tell me what you think, or if it is possible.

1. 87 GT heads**ported (if they will fit???) (recomendations)
2. four barrel carb set up (stock 83-85 intake**ported) 650 holley carb
3. b 303 or e 303 roller cam
4. the block rebuilt, balanced and blueprinted

what do you think this will run (hp, torque)
please keep in mind I am building this to be a cruiser not a drag car....

thanks for any info