Who makes/sells these Powerglides for offshore applications? I can call them to see what HP ratings they make and whether they fit right into a velvet drive application without modifying the engine placement.

dont know what a velvet drive looks like but the power glide would handle any power you could put in a boat.

i would have to look but i think my power glides were around 4500.

How does shifting work in a twin application? I would think they need to shift simultaneously to prevent boat from getting out of shape.

Is shifting a manual thing? A button?

I think the shifting was with a switch but it is usually done as you came on plane. You would shift at the same time but if there were a little difference then I don't think it would make much difference at such low speed.

I heard the B&M 2 speed was actually a chrysler torqueflight transmission.

The GM powerglide is one of the most developed trans around, very popular in high hp drag racing.

vtec

I am running B&M two speeds on a cat with number sixes and big HP. Low gear is terrific for off plane. I come off plane and shift at about 40 mph. top end in first is about 60 as it is a real low gear. The boat has 1.35 gears 34 pitch props and jumps out the hole. HARD!!! Shift is electronic with a switch on the floor like the old headlight dimmers in the 60's cars. We did blow the pump out of one because it was not lined up on the drive shaft. Need to dial indicate the crank to the bell housing exactly! There is no torque convertor. So far so good. I have mixed feelings about them. Pissed that they are so critcal on installation and love them when I shift. B&M does not make them anymore but there is a company that bought that division and still makes them.
They are Torqueflights. Built to handle around 1000hp.

Thanks, that's the info I was looking for. Too bad about them being finicky. How many hours do you have on them so far? Any other people you know use them with big power?

Six seasons. I have not seen another, probably because of the cost.

Forgive me for hijacking this thread for commercial use, but we have 3 of them for sale in the classifieds.