you should have no problem making 550 rwhp with 60s....I had 60s and a 6765 in my WH1 Otto tuned....and It made 556 rwhp and 600 LBS of torque at 22 lbs boost 0 knock Another lb or 2...600hp no problemI'm keeping my 60's and the stock ecm for my next build and if I don't make at least 600rwhp, it'll be a dissapointment. It won't be a record breaker, but I'm not anticipating any issues.
EDIT: Probably closer to 550rwhp. What does it take to go 130mph? 135? I think it takes almost 900 to go over 150mph in a full weight car.