Two speed transmission?

[powerplay230]

Size (length having to move motor forward), weight? sure there are some arguments to that but I bet a powerglide is much longer than a marine 2 spd (B&M)? Would be pretty cool to hit overdrive when cruising tho'.. :idea:

[OLDRAT]

Yes, B&M made some marinized transmissions for a couple of years.
If you want a powerglide, find a "shorty" from some of the rail dragster
guys at a good price. They made two versions from chevy; long and short
tailshaft, but the shorty drag style has an even shorter output shaft and
a flat bearing plate that bolts to the transmission case.
They do take a lot of abuse. Don't need the converter, just need to
get a marine adapter with the internal splined shaft that will bolt up to
the flex plate. If you are using it with an outdrive, just set the shifter up
for neutral, low and high. Drive will take care of reverse and well, the park
setting..... Also, there were two factory gear ratios and I know there
are many more custom ratios. Just loop the cooler lines or run them
thru a small heat exchanger if the boat is going to see a lot load.
A-1 Transmissions (Marv Ripes) was the guru at one time in So Cal.
Good Luck,
OR

[kranedoc]

i am running a b&m 2 speed with 1000 hp motor no problems

[Bob Hostetter]

The are a couple of different transmissions that can be nade to work in a boat. But keep in mind a trans is a torque multiplier and sterndrives don't like a lot of torque.........

[oknozelman]

kranedoc, What drive are you running? What kind of transmission are you using? If it is a power glid are you using a converter or a torque tube?
Hostetter, Will a #5 hold the torque from a transmission? What are the kinds of two speed's that will work?

[Gmoney]

I wonder how much more power it would take to turn a powerglide campared to a marine single speed trans like a 72c velvet drive tranny. Im thinking powerglide to a arneson surface drive would be a bad ass combo!

[powerplay230]

Powerglides are very efficient and can be made almost bullet-proof, ask the drag racers..

[Bob Hostetter]

There area couple of different ones out there.
A power glide can be built very short and just about unbreakable, but they tend to have a fairly large step between gears. I am sure aftermarket gears are available but don't know what ratio's are available.
The Turbo 400's can be made to work but the length is an issue. You normally see they used in v-drive day cruiser's where the length is not as much a problem.
Lenco 2 speeds work well but for non drag racing applications you will probably need to rig up some form of cooling.
As someone else mentioned B&M made one for a while, don't know if it is still available.
Mercury has one they either make or use for some of their racing setup's with the #6 drive, you would have to contact them directly for info.
All outdrives will break if you push enough torque thru them. That is why even the off shore race boats take it easy untill they get on plane. Not sure what the #5 is rated at but depending on your engine's torque/horsepower and the gear ratio in whatever trans you use, you will either snap the shafts or the gears if you hammer it.The general rule seems to be if you are going to hot rod a high powered outdrive, plan on buying lots of outdrive units. The #5 is a lot better then say a Bravo or a XR but it will still break if you push it hard enough. Thats why GOD invented v-drives and surface drives...........

[kranedoc]

i am running a 2 speed b&m transmission which is a powerglide tranny with B&M bellhousing. It has a top mounted starter and no torque converter but it has a torque plate which looks like a clutch but bolts to the fly wheel. Outdrive is a speed master 3A and the motor is a twin turbo 1000 hp. I run it hard out of the hole and have not had any drive problems. it is nice to have the 2 speed when in the marina and docking. pulling skiers its great to. on the flip side you lose a little hp out the prop. if you have any questions on these you can call brummett marine in pasadena ca.

[oknozelman]

Hostetter, Do you know a guy at Mercruiser named Woody Smith? And is Mercuy Racing using a two seed on the race boat's?
Kranedoc, I would like to see a pic of your engine and trans setup. Does the trans shift well around the dock or is it clunky? What type of boat are you running?