Help on transmissions for V Drives.

[delusional502]

I hope someone out there will be able to help me on this one.
I'm after info on F-N-R transmissions for a v drive application.
HP is around 700 or so and the boat will only be used for social skiing and the occassional blast up the river.
If any of you guys know where I can get something and for what sort of money it would be greatly appreciated.
Thanks in advance.

[coolchange]

My chioce is a Powerglide. I dont need to shift but low is nice for the 5 mph. Most run TH 400. Has a closer 2-3 split for a useable 2 speed. TH 350 has closer 1-2 then a wide 2-3 split which doesnt make for a good boat application. The Velvet drive is standard marine trans but takes a lot of power to turn. Powerglide has the least parasitic loss.

[Bob Hostetter]

I use a velvet drive in my Hallet v drive, but i don't run 700 hp. I am running closer to 475-500hp. It has worked well for many, many years......

[Jet City]

Not sure this is very helpfull, but I run a modified THM400, has a manual reverse valve body which is nice for jockying between 1st and reverse, other than docking 1st is useless, I like to take off in 2nd and quickly grab 3rd. I haven't had this boat too long, but so far the THM400 has been good to me. I probably have near 500HP as well, next summer I hope to have 550+hp.
I know most people claim reverse cannot be used in these boats, I find mine useful and have not had any troubles with water over the transom in reverse, the tranny sure gets alot of attention at stores and service stations.

[Morg]

My tranny has given my years of trouble free service. I call it a "Paddle" :hammer2: :hammer2:

[mach1alaska]

My hallett has a F-N-R box instead of just F-N it is an original casale box on the output side of the drive. I don't know how easy they are to find I believe mine came in the boat when new.

[Lake Ape]

Powerglides are available to take any horsepower that you can throw at them, they even run them behind the old top fuelers. The TH400 is also a good choice and will easily live behind the 700 hp if built correctly. The same can be said for the th350 but it's much more expensive to make reliable than the other two at that horsepower rating but it can be done. I assume you are running either a chevy or ford but I have used the TF727 successfully in many, many high horsepower appliacations, it's pretty stout. I would stay away from the velvet or other marine drive, although pretty simple, they will still cost you more to work on than the other car based trans. My personal choice is the powerglide since you can get it completely custom, even totally billet and it's very simple and super stout. :D

[steelcomp]

With all the aftermarket PG parts available, can't you get a taller first for a PG to make the 1-2 more useful?

[GofastRacer]

The TH400 is the only way to go period!. PG's are junk, they were made for six bangers and 283 small blocks. To make them worthy of horsepower you have to replace evreything with aftermarket parts which costs tons and you still have way too much of a spread between gears!. The TH400 is stout to begin with and only needs minor modifications for trouble free service for 700 to 800HP!. And you have a good gear split from second to third and low gear for the dock area!... :smile:

[VD CRUISER]

What Gofastracer said, can't beat the TH 400 for the money. I do have a buddy using the Velvet Drive behind a blown 540 in a Schiada , with no problems, though.

[Thunderbutt]

If you decide on the velvet drive I have a new rebuilt one that I'd make you a good deal on. It would handel the 700 hp. If you have a flatbottom do what Morg said

[fastsanger]

i have 900 hp in my daytona with a mikes transmission th 400 love that tranny (mikes transmission in lancaster 661-723-0081)

[johnmiller]

You didn't mention what kind of a hull you have. If you have a low profile flatbottom, you are better off with a powerglide/TH400 rather than a velva-drive trans. Reverse is much safer and easier to use because of the gear reduction. A borgWarner velva-drive is 1 to 1 in reverse. If you have a room problem, then the powerglide is a better choice. I have been using a powerglide in my 21 year old v-drive with no problems. I bought it from a company called A1 racing transmissions in Canoga Park, CA., don't know if they are still in business. It uses a special direct adapter eliminating the TC and the rear of the trans case is replaced with a machined plate, making it very short. It is also much lighter than a velva-drive and TH400.
The only negative with car transmissions in a boat, is neutral. The prop turns in neutral, so put it in park when starting the motor on the trailer.
As far as strength and reliability, I see no problem with a powerglide. Keep in mind a boat can not produce the stress and strain a car can apply to the trans!