**600hp sbm block limit? Or is it bs!!**

I am running a 73 340 block with main studs only, and no hard block. It has a 3.79 stroke crank ,10.9 comp and 360-2 Indy heads pump 93 gas. According to the Wallace Racing calculators I am making around 625 hp going by my mph. On the dyno with a 1050 dom. it made 662 at 7300. I am running a 950 carb now with a stock mechanical fuel pump and autozone fuel filter. That may be holding me back compared to the dyno numbers. Best E.T. so far has been 6.29@109 with 1.33 60 ft. at 2950 lbs. driven 40 mile round trip to track. It is not a A-body.
I want to try a little N.O.S. and get a 5.9x in the 1/8. Maybe 100 shot. Maybe my stock block will hold up..