I didn't mean that adding a small amount of HP is hard to determine, I meant that dyno's - even the same dyno - can fluctuate by a few HP depending on conditions so it is difficult to tell if the changes you see with small increments are indeed attributed to the mod or the changes in conditions between the dyno pulls.

Hopefully you all understand that the butterflys without the Deletes are completely open at WOT and dyno pulls are made at WOT. So the only chance for the deletes to provide better flow is when NOT in WOT and/or during the periods they open/close. That is the only place (not WOT) where the deletes are offerring any difference what-so-ever from the stock assembly.

Rock - you are correct, the HP and torque are tied together mathmatically but there is no way to determine IMO that change if any on a dyno as the pulls are made under WOT.