Looking to buy/build 500-600 fwhp 360

i thought 400 hp from a 360 was a mild build,...easy as falling off a truck!!
I just want to build it strong enough to handle the 200 hp nitrous shot and live. I don't necessarily want 450 hp on the motor by porting heads, big cam, etc. I have a 690 hp corvette. It has a roller cam, extensive head work to the AFR heads, etc and I just can't hook it up without drag slicks. I'm just thinking stout internals to handle the extra pressures of nitrous, and drive it around town on 400 hp.