Calum has had several cars on the dynos, ask the guy. He's very cool, very honest, and extremely smart. I did my setup (just) before Calum came along; Dre made me set the MSD Digital 6+ at 7500 (or else :-) ) the way we set up the stock cam motor with the japanese headers and truck maf. It's stronger at 7500 than the next gear up at whatever lower revs it happens to be. Can you TAKE it to 8 or 8.3? No doubt. Actually probably for a good while, but how often do you want to take it apart? If you like pulling it down a lot, take it to the springs limit which is about 8500. I've torn motors down a fair bunch, so I'm not big on it any more, personally; I like 'em to stay together for a while these days. Just depends on how much you like getting greasy.