Sorry for the confusion, have not seen that design for sale, but yes they almost always make "some" difference. I have never put a tapered Spacer, whether it be an HVH or a Wilson on motor on dyno & not have it do SOMETHING positive.. gains like 15HP are rare. Normally you see 4-6 TQ/HP. Maybe 8-10 sometimes....
Ryan have you run a (we will say) a standard 4 hole
then run a tapered in a back to back on the dyno,
I'm sure it might be the added velocity in either
to get a better TQ/HP ... at least thats what I seen
when I was doing headers on the dyno but we played
with some spacer also but you have more dyno time
than I do
