I have the pipe tuned for a 10x6 APC, which turns 18,200 or better on my 15/20 fuel. My buddy suggested a Pylon APC prop - maybe 9.5x8 or something close. The pylon props have a thicker hub and wider blades than the regular 9” props do.

I put my .56 on Kurt’s SI3 .60 after I ran it in mine. His ran 10mph faster than mine (his ran 55 IIRC). This was only the second time the engine had been on the water. It’s still tight as a frogs butt, so I was running it a bit fat. It was peaking just barely on the pipe.

I need to run the .56 on the rigger, but I gotta get another set of hands to launch it for me. Life has had it on hold for some time. I’ll have to reconnect with Kurt sometime.