351c or clevor???

Hey everyone, new to this site and looking for some advise on whether or not to scrape my cleveland that i've had for about 8 yrs. and is now time rebuild due to head & block damage. First off i would like to build another cleveland but blocks are hard to come by here in especially 4 bolt mains. found a 2 bolt but haven't seen it yet and not sure if its cracked or suitable for the amount of power i want in end result (500hp). Second do i go the way of building a clevor and try and save $ and the some parts already invested: namely headers, distributor, or whatever that can fit. ????? Thanks for all your time and any suggestion or knowledge on the subject is greatly appreicated.