I think a stud girdle would increase how far you could push it. Once I get the cage and stuff in mine, I plan on juicing it with a 100 or 150 shot, which will push it well above 600HP. I only spin mine a little past 6K.
I don't know about the girdle. The one Hughes sells will not do much because the contact at the top of the Main Caps is Minimal, even when doing there secondary method of machining the top of the stock caps instead of using their spacers. There is someone on here that makes a really good Girdle with matching machined aftermarket caps that contact the girdle all the way across the caps.
Yes you will be well over 600HP when you Juice that engine!
