GM 350TH automatic tranny

[l_boyle]

I am just curious.... Have anyone ever installed Chevy 350 cid marinized engine along with automatic tranny from a car in their inboard cruiser?
I would think it would give variable speed over the rpm ranges as well the load on the boat it self... I am sure that 16" to 20" dia. prop would be the issue for the set up.
I am thinking that you may need a shaft brake to the shaft from turning in order to shift from drive to reverse and vice verus. The craft is on water, tranny doesn't need the parking pawl.

Wow, could anyone image "slamming it into reverse while going forward at high speed"... Hang On!!!!

[stevel]

They were usually TH400s, but that was done all the time with v-drive boats. With a direct-drive, you would need to add an external thrust bearing. I don't know that there is any particular advantage to mutiple gears in most applications, but you will have to talk to the racers about that.

[stonebreaker]

Would you need a torque converter? Or would the prop act as the converter?

[stevel]

Originally Posted by stonebreaker

Would you need a torque converter? Or would the prop act as the converter?

Many were run with converters, but the prop does a fine job of acting as the converster. During my time at the boat shop, I once installed a welded coupler that replaced the converter so that the connection was solid. I don't recall who sells those, but a quick Google search should find a source.

[l_boyle]

Actually using a torque convertor in the set up, along with universal joints, shaft log, straight shaft to the prop.. I didn't mentioned V-drives. Just straight shaft through the keel at 15 degrees. Because shifting with inboard set up that have a direct drive, sounded like Ol' Freddie Cougar chewing on his steel fingernails, or marbles rolling down the washboard.
That is a sickening sound that I hear in most boats with direct drives with forward and reverse 2:1 ratio tranny. Grind 'em till in fits....

[MntFisher]

never seen a 3speed auto, but we put alot of powerglides in boats. thats a 2speed auto. Look at dirt track supplies for a coupler to use in place of torque converter.

Chris