I have 1983 Winner 17ft, 150 V6 Blackmax,with jackplate and dolphin hydros.With GPS 55mph at 3/4 throttel trimed up at 4700 to 4800 rpm.This prop has no pitch stamped on it,it has been worked up at some point.Took it to local prop shop to have vent holes drilled in it.I do not have any hole shot at all takes it a few seconds to plan off.But once on plane will run its bass off don't know for sure, but it feels like 65 to 70mph at WOT. Drilling the vent holes helped a little on the hole shot but I need more.The fellow at the prop shop said it had been a long time scence he had seen one worked up like this.He said that he thought it was a worked 28p. with lots of rake and cup added to it.What would have came on this motor stock.Thank, Joe