Flathead intake question.

I read here and there that a Thickstun PM7 is smoother and has a better top-end response than say, an Offy Regular Dual. Both manifolds have approx the same carb spacing, so basically the difference is the height of the runners. Do the longer runners really make a noticeable difference to performance?

 

I can feel it give more torque at low and mid range but more important for me it keep the generator in the stock place.
My PM7.