Looking to buy/build 500-600 fwhp 360

To keep from affecting your engine parameters too much, I would alter the compression by getting a larger combustion chamber so you can obtain a near zero deck and have good quench. With nitrous and that much compression, you may need a custom grind LSA to get the most benefit out of your combo. I built a big NMCA SBF stroker for a customer of mine back in the late 1990's that had almost 14:1 compression and was spraying 400 horse Nitrous Works fogger on top of it. It's all in the cam.
Hmmm. Hughes engines does a mild porting which enlarges the cylinder volume by 8 cc's. That should give me low 10's compression ratio. Then I can run a hotter cam with a wider lobe separation. Most of my driving will be street. I can give it a squirt of nitrous at the track for an addtional 125 hp or so. It's a manual trans car so idle can be a little unruly. No power brakes or power steering. There is a 408 motor on the dyno page of Hughes engines but I think the cam number is an old outdated number.