Gentlemen I was hoping someone could give me some idea on props in or out. I have a straight bottom 43 Scarab with trip 850's & #5 drives & 17x31 4 blade props. The nose cones are roughly 3.5" below the running surface of the hull. I've tried raising the lowers 2" by removing the 2" spacer but that really didn't seem to help & the prop slip went into the 18% range. With the spacer back in the slip is in the 12% range. But the old girls heavy a** feels like it's just stuck in the water. It never really gets loosened up. Any help would be appreated. I have some big tube headers coming & have just installed 10-71 BDS blowers & plan to turn the boast up to 10 psi which should bump the motors up to 950-1000 each. By the way I'm at 92 on gps right now. Thanks.

start with some modern day large diameter 5 blade props. work with a prop shop...i know if you buy props from someone like cobra, you can exchange them.

look under the water line....there is WAY more there to be had than where your currently looking above(ie engine).

good luck

i run mine out 42 fountain triple 540s

O.K. that's one sugestion to turn the props out,thankyou. I will assume audacity is talking about Cobra engines which I'll contact. But how about just telling me what your talking about below the water line I'm not racing just looking for straight forward suggestions.Thankyou.

I'd think again about running 10 lbs boost.....$$$$$$ repairs

bottom of the boat/hull in relation to the surface of the water. also set-up; where the props are in relation to the bottom of the boat and each other. what props. weight...ect

just trying to say, people seem to want to increase HP prior to looking at set-ups and the bottoms.

i would never assume your props should turn one way vs. another without seeing/running the boat first hand. even if i owned the same boat. too many variables.

good luck!

Thankyou for all you guys help but the 10 psi boast don't bother me I have Jack Roush helping me with the motors. As for the set-up I've said that they are 17x31 4 blades & the nose cones are roughly 3.5" below the running surface of the hull. There are no stand-off boxes. I'm not trying to set on the pole at Talledaga I've already done that. I just want to get my boat a little closer than what Wellcraft sent it out the door.

Ran a 36 baja with #5 540 blown 860 hp, had stand off boxes, 4 blade cleavers 2 inch spacers. Took long time to get out of the hole, but it ran faster and better with props turning out, tried in and hard to get out of hole and slower top speed by 5 mph 98 out 93 in. Is smaller boat but may help, bottom was blue printed too.

Thankyou Scooter that is info that I can use even if it's a smaller boat. Thanks again.

what gear ratio...how fast...what rpm...what is your set-back from the running surface...what is the toe-in/out in relation to propshaft centerline...what is it in relation to skeg...what are your props center to center...these all very important measurements and factors.

how is the bottom of the boat...huge variable and can not ascertained via a phone conversation nor here in the forms.

what does it weigh?


JR is helping you with engines? then you are around detroit?