I originally removed a 3 blade nickle leading edge taper tip Warp off my model 4 and replaced it with a little longer blade Kiev on my 80 hp 912. It didn't work out too well so I quickly sold it to a friend who installed it on his 100 hp Paradise P-1. I then purchased the shorter proper length Kiev . The performance has been great (after a few pitch adjustments) No way I will go back to the Warp as it was too heavy and not nearly as smooth or pretty as my Kiev.
3 guys in my area have swapped their Warps for the Kiev and they have all been very happy. I think you will like it. I wish I could give you the length but I am away on vacation and don't have access to any info.
Go on the Kiev web site or call Ted Bryant @ Kiev. He was extremely helpfull .They have a chart on the web site that will help you with selection.
Dick