maniac0586

hello all, i have a few questions about what drive i should be running. I bought a 87" Lavey Craft 20.8 Sebring tunnel that has a 454 basically stock. with a what i believe is a Bravo 1 with Imco steering. I think the motor is making probably about 350-400hp. What i want to do is upgrade the motor this winter to about 6-700 hp and I'm really not sure what to do with the drive or what one to go with. i know that it is internally shiftable and would like to keep it that way don't want a tranny. so any idea? would be great if i could keep the gimble all the same also just unbolt and rebolt the new. Also i do know that it has 1.5 gearing probably could use a taller gear because in already running a 27p mirage plus 3 blade and pulling 5100 rpm. thanks!!

Mr Gadgets

Thats a light boat.. I would think. A properly built B1 with X gears would work nicely..

Dick

maniac0586

well what are X gears? right now i know that the upper has Imco gears because when i bought the boat first day out it had a broken tooth on one so i had them replaced with imco gears.

Mr Gadgets

The X gears are the new generation of thick floored gears. They came out in 2000-2001. You can tell if you have them, by removing the top cover and looking at the thrust needle bearing on top of the, top, driven gear. If the needles look to be .125" versus .078", then you have the new thick floored (as I call them, X gears).
Imco used to take the old style gear and reweld them and change the thrust bearing to one with even larger needles. But usually only the lower gear, sometimes both driven gears.

The strongest way to change the gear ratio is swapping out the lower gears. The 1.36 upper gear set has smaller teeth on the gears.. They are actually shorter.
So a B1 with a steel tower and X gears and a good top cap with steel tower is what I was thinking.

Dick

pantera232

How are you getting so many rpms out of a stock carburated 454. I thought they were only pusning low 300's in hp