I just budget built a 6.0 that is around that HP, I bought used and redid top end. I have a 2.68 with a 79" 3 bld R it is on a 14' Alumitec runs fairly well. It is certainly not purpose built, might blow-up tomorrow. Had a stock 5.3 that had 113K before it was on 2 different boats over 300hrs on 1 and 192hrs on mine, still running strong when it came off a month ago.
You can get LS2 Block from scoggins-dickey for 1200.00 and LSA forged crank for just over 400.00. Look at the the Scoggins web-site they have some good pricing.
Sent you a PM
OEG