22 DAYTONA

That sounds like about 600Hp, or the set up is very wrong. the above boat will do that speed full of people, beer, and fuel in the heat. It just takes it longer to get there.

zx14

maybe the speedo is off? the prop is a 32 and pulling it to almost 6000 rpm takes some HP????

I dont know my gear ratio but I can cruz at 38mph at 2700 rpm

DonRoc

Your speedo is off, or the prop is slipping a bit much. with 1.5 gears top speed @ 5800 should be around 103, Cruise @ 2700 should be near 48mph. With your setup I would guess 750hp. I worked on a 540 with AFR heads, a M3 9psi that made 840hp on the dyno. And that seems to work with the numbers you should be running at that rpm.

zx14

thanks for your input. motor is suppost to be 540 cu in it has a lumpy cam but idels at 900 ok, dart pro 1 heads , M1 procharger, 60 lbs injectors,msd , the mcu was done by arizona speed and marine. I am thinking I may be only doing 5000 rpm, I am going back to the lake saturday

DonRoc

5000 is a long way fom 6000 in your last post. Still things dont ad up. And the M1 is running pretty hard to make 750hp.
Take a good GPS with you, and a note pad to with you to write things down, (speed, rpm, drive ratio, prop, conditions, fuel and people on board).
Good luck. I should know if I am getting the 27 this weekend

zx14

Thanks Don. there is no marking on the drive for the ratio, is there a ez way to fiquer it out?

good luck with the 27!

I have had 2 - 21' daytonas a 25' daytona and now this 26'. If even at 0nly 100mph This one is the most stable.roomy and rides best. "damn sexy looking too"

skydog

Yes i too would like to know!!

DonRoc

Put it in gear mark the prop shaft, turn the motor over from TDC to TDC one revaluation. See how far the prop shaft turns. 240 degrees is a 1.5 ratio, 267 deg is a 1.35 ratio. If it comes out of gear hard don't force it, Hook up a remote starter and start it in gear then shift to neutral, this is best done on a hose.

zx14

ahhhh, so it is 1 revolution of the prop is ether 1.5 or 1.3 revolutions of the engine. I always thought is was the other way around.

DonRoc

Yep, Remember going to a 1.35 from a 1.5 is like running your car in a higher gear. Not lower as your thinking would have it. So the lower the gear ratio number the slower the engine will run all things being equal.It puts more load on the motor. The gear ratio from 1.5 to 1.35 is about the same as the 1.5 and 3" of pitch more. So a 1.35 with a 27p prop will run the same as a 1.5 with a 30p prop. All you need the ratio for is figuring slip if you care.
I need it because I dont want to run a 37p prop, it leaves me with not many options. So I went with 1.35 and a 34