Power loss. 318 Vs 340 manifolds

With my combo I went from a 11.78 @ 118mph (Slicks, 3" exhaust, SuperComp hearers) to 13.2 @ 105mph (340 Manifolds, 2.5" exhaust and E70-14 RedLines)

I think I could get a bit better time but the E70-14s are a ***** to launch on.