Your fountain performance report will have X dimension on it. I should add that I think raising your drive will increase prop slip... possibly losing more speed? Interested to hear what others think.

Sounds like your so high in terms of slip that a 5 blade is the way to go. Testing is the only way when dialing in. You can ask a million questions, but untill you bolt the prop on, you are not going to know. Also keep in mind, that you went with a 250lbs lighter motor, so sternlift is most likely not the way to got. Dp you know how much your B1 is pitched up. Personally I'd run a stock 28 B1(27"-27.3") and a 15 5/8 X 26" Maxie. The 90$ that's going to cost are money very well spent to get some accurate numbers.

Give me a call we can help you out.

Just curious if you called Reggie or Wyatt Fountain to get dialed in correctly.

I talk to Reggie shortly after he posted that reply and I thought I should maybe try a 5 bladed prop. He said it would definitely get rid of the slip. He also thought if I go with a 5 bladed prop I might want to try a shorter outdrive at the same time. He told me that I’m just going to have to play around with it and see.
At the beginning of June I’m planning on trying a IMCO -2 lower and a Herring 5 bladed 25p and I’ll go from there.

That makes sense, let me know how that works out, my friend with the same boat as yours is having the same problem.,w/ a 525 EFI single, Bravo1 prop, has tried both 26 & 28 pitch props

You got it!

I know it's been a little while since I've posted something on this subject but I've been out of commission do to a back injury. Anyway I decided to take Reggie's advice and try a 5 bladed prop with a shorter outdrive. It turns out that I've been running a 1.34 gear ratio and not a 1.50 so Troy setup the new lower with the same gear ratio. So our first run was with a -2 lower and a 5 bladed Herring 25p. Slow to plan and top speed of 73mph with an RPM of 5000. The WOT range on the Ilmor 625 is between 5800 and 6000 so we're way off. On a positive note the slip has come down quite a bit from my previous run at 27% (26p 1.34gr and 81mph) but unfortunately it's still a little high at 17%. I'm having Troy change the gear ratio to 1.50 and we'll try again next week.

Send us some pictures. Im interested in seeing how it urns out as well.

:food-smiley-007: Great thread to read, awesome project, keep us posted.