Yes! That is what I've been trying to find out. For your application that sounds correct. My car will be mostly track driven and high rpm abused. When you say retarded do you mean just the intake or exhaust lobe or just in general? And are the 3.5 and 4.5 the same grind? If you have a spec sheet you drew up I'd still love to see it. I'll be running mechanical most likely. Maybe I can find a grinder for a reasonable price.