I truly think S&R builds a responsive and responsible kit. Obviously the sky's the limit on how much power you wish to produce. He just allowed that they got 658hp out of a stock block with 100 octane.
Now that's on the edge, and the same person made 647hp before his valves came raining out of the stock block. (I know who he is and he's very selective about what info he lets on about on the forums or otherwise. Claims all is well from the first build. Says he hasn't gotten to the track yet. (He's gunning for me.) I was told privately otherwise. Some people don't show all their cards.)
Mr. Squeeze is right on: Mine
detonated @ 590whp and bent all the rods. Fortunately that's ALL that happened. Whew. (New tuner = safer tune = less HP =quicker ET. Go figure.) I have rods, pistons, studs, balanced, etc. now. Built and with more room to go.
My point is, it's out of control of the shop what the limits are if the boost is available to change. It's like giving my ten-year-old the cookie jar and informing him to eat only one every hour. Ummmmmm.....
That said, the dyno is easier on the engine than the strip or highway. Tread water carefully above 550.
Good luck with this kit. It looks well made and in the right hands will last forever.
Coop