That's cool, that's what I'm making at 6500 and Bob got it making 486 whp. I have Cobra rods and pistons like you. You might be able to make more, he said the P1SC that came with these Mach 1 kits are not as efficient as the regular P1SC. He will get as much as safely possible, I really can't say enough good things about him. Probably the best Ford tuner in a 1500 mile radius.