prop size

[steve paull]

I am trying to determine the prop size i should use on my 1976 26' sleekcraft w/v-drive. It has a fresh 454 motor, a velvet drive tranny ( 1 to 1 ratio), and a champion v-drive ( 1 to 1.04 ratio)
right now I can only reach about 4500pm. I think I should be able to run 4800 to 5200 rpm easily.
does anyone out there have any idea's for me?
Wanting more rpm and speed,
Steve Paull

[Sangster]

Look at the top of this page and call them ask for Tom Bentley. He's the Man when it comes to that stuff....
{aka. "v-drive Tom" on the boards)

[V-Drive Tom]

Mr. Steve Paull, You haven't said what prop you are using now. You need a large dia. because you have a big heavy boat to move. So 13inch dia would be good,or more if you have the room, to keep it about a 1/2inch from the bottom of the boat.(3/8 min.) If your engine is very stronge you are going to want a 15 or 16 pitch. A brass prop will work OK, but a steel prop will work better even if it is the same dimensions. TOM..

[Lumpy]

V-drive Tom,
I have an 18 foot flatbottom. The engine is a 427 single carb. Right now I have a 3 blade 12x15 brass prop. My max rpm is 4700. I am not sure what gears are in the v-drive. Approximately how much top speed and rpm would I gain by going to a 2 blade prop? Thanks....Lumpy

[V-Drive Tom]

Lumpy, You have too much gear in the v-drive. There is no reason that your engine(with a brass prop)shouldn't be running at least 5800 RPM. If you don't adress the gear ratio, your not going to get the most out of your boat. A 2-blade will raise your RPM 2or300+, and gain 5 or so MPH.(IN THE PROPER COMBINATION) TOM..