The prop specs thread has several Saltares in it, so you might check out that sticky:
https://forum.supraboats.com/showthr...rop-Specs-ONLY
If your slipping with a 13x13, you may have something funny going on. What is the gap between your strut and the back side of the prop? This should be less than 1", on mine it's more like 1/8". That dimension isn't actually what's important, but indirectly affects what is important to prop efficiency - distance from hull. You're not going to get a lot more than 40 MPH out of these boats no matter what you do.
I've personally run these two props on my '86 Saltare with 454 - which is probably not as healthy as your freshly built engine:
ACME 209 4 Blade 13" x 12.5" 0.080 cup: WOT unloaded: 4500RPM at 37.5MPH (ridesteady digital readout, GPS). 11.2MPH at ~2600RPM with ~1900lb ballast and wake sharper for surfing. Seems like it's working pretty hard, nearly not doable with more than 3 extra bodies onboard. No chance in the world of getting on plane with that weight.
Acme 1229 13x11" 0.080" cup 3 blade. WOT Unloaded: 4600RPM at 41.0MPH. Yes, it sped up and only turns 100 more R's than my old 209. I don't quite understand it, but it's true! The boat is "throw you out of the observer's seat" fast out of the hole now. Seems to cruise pretty happily unloaded at 2600RPM at 25-26MPH. Fuel consumption makes it seem like it's not in the secondaries of the carb, therefore still fairly economical.
With mixed use, i run about 10GPH, or a little better.
Also, how are you measuring speeds? if it's from the stock speedometers, have you calibrated to GPS or the old school timing method? If not, throw your readings away.
Last edited by korey; 10-10-2017 at 02:26 PM.
Korey Morris -
Sold to Arkansas: 1986 Supra Saltare
Current: 2018 Moomba Craz