What should I do?????

Why don't you go with a DSS Long block. I think it would make more power then a FRPP crate engine.

Personally, I don't see anything at all wrong with the FRPP long block. I like that it's a "turn Key" solution. Everything from the Dizzy right on down to the oil pan plugs. The 347 is their only offering with forged pistons (good). The crank is forged as well (overkill). The combination is all designed to work well together and even with the 10.5:1 compression, it should take a mild amount of boost. If it were me, I'd still look at CHP and DSS just for cost comparision. Who cares what heads this guy is using or what cam that guy is using if you're already at 450 HP N/A... Nothing short of a 4 bolt block is going to be safe beyond that HP anyway. So long as you're good with the cost... go for it. My only tip would be to put a stud girdle on that bad boy if it's not got one already.