[KingLT1]

Originally Posted by Joshinator99

Agree 100%

I always thought the advice from the late, great, John Lingenfelter was always sage: “Build torque in the RPM band at which the car will spend most of its time”. Since torque is simply airflow plus timing, it’s not hard to get where you want to go.

Originally Posted by GreyGhost702

That was kind of my point, pulley combo for pulley combo the D1X was going to always outpace the D1SC. Somewhat similarly for a P1X vs D1SC, in terms of efficiency (cooler IAT's for the P1X over the D1SC pound for pound). Though without a real world comparison, not sure if a maxed out P1X would still operate cooler than a maxed out D1SC. I think it would, but reality vs theory.

I wasn't aware OP was going to be boosting the SBE, so if the target boost range is 8-10psi then yeah the D1SC all day exactly as you said, why give up any low end boost if you don't have to. D1SC won't really start to cook the air 'til after 14psi, so there's still room to grow. The D1SC can always be upgraded to a D1X if the OP wanted to go that route after an engine build, too.