In my oppinion.
I would say that the heads are restricting that engne it could maybe make 800hp with alot more boost and different heads. If the 452:s are not ported they don't flow that good. If I remember correct 650NA horses is good with max ported mopar 452 heads (might remember wrong) . then if you slap a blower on it it could make about 1000 with much boost and other parts.
I did not see in the text if he had billet main caps or a stud girdle? I consider that a must for BB mopar over 600hp on a stock block. (better safe then sorry)
And what's up with the non reinforced 8 3/4? ok it's narrowed that helps but still?? seen those housings twist...
I would think it can run 10's with spinning the sXXt out off the blower and hoping that it does not make too much heat...
anywayst that is only my oppinion...