They say that you gain 4 to 6 HP
but that up to debate IMO and beside they arn't my manifold. Mine are only tested on my bike on a Dyno
and with a stock carb
jetted properly, my ported manifold and a dyna
3000 it put out 75HP 98Lbs Tq and hit 130 mph on the dyno. The TQ was down because of short pipes a 2 in 1 would have given 100+Tq.
I am not say the manifold will give you those number without the other components but you can feel it.