451 BB build OPINIONS!!

I am building a 451 street motor...440 forged crank and ly rods srp forged alum. pistons with a comp cam 564 lift hyd w/ 1.6 stainless roller tip rocker for a final .601 lift I am spending the money for the heads though...Indy 440 EZ and port work by Knowltans. A Friend did this exact build and got 620 hp! His motor sounds tamer than my 440 / 292 509 motor but churns out about 100 more horse and torque!