Hydromatic ????'S

[Deleted User]

My Wifes' car is a 53 4 door Hornet 308/Twin H / Hydromatic, an I'm thinking of putting a 390 Caddie motor with Tri-Power in it, I have the 390 and the Hydromatic that came form the Caddie, Both the Hudson tranny and the Caddie tranny have removable belhousings, I'm wondering if I can just swap belhousings and use the Hudson tranny with the Caddie motor. And will the Hudson Hydromatic hold up to the Caddie power and torque? My old '54 Caddie had what looked like the exact same tranny as the 53 Hudson.

Ol racer

You have a good thought. The Hudson Hydromatic was built by GM so it probably will interchange. I doubt GM built a different input shaft and Torus just for Hudson instead Hudson probably made a flywheel to fit the Hydro....

RL Chilton

Ol racer wrote:

You have a good thought. The Hudson Hydromatic was built by GM so it probably will interchange. I doubt GM built a different input shaft and Torus just for Hudson instead Hudson probably made a flywheel to fit the Hydro....

That's my impression, as well. When doing Dany Spring's conversion, I know a different flywheel is to be used. Should be the same application with the caddy tranny.

[Deleted User]

can you elaborate on "Dany Spring's conversion"

RL Chilton

Dany Spring, owner of K-Gap. Do a search here on the forum and I'm sure the link will come up. They make a nice conversion for a GM modern tranny to fit onto a Hudson block.

[Deleted User]

im not entirely sure but i think that the bell that came with your trans has to stay with your trans to stop alignment problems. if you can- use the caddy trans, it has more clutch discs and 4 rather than 3 sun gears in the planetary

Unknown

There may be a few other that you may need to check:when swapping out the bellhousing, you will have to remove the torus cover and assembly which calls for a large socket and snapring pliers. I would check the torus cover bolt circle diameter,hudson used up thru 1954 a 5/16 bolt {30} 1955 and later used 3/8 bolts, not sure on Caddy. Caddy also used a large O ring to seal torus cover to flywheel, where as Hudson used a gasket. Most of which you will findout during dissassembly. The mainshaft nut needs to be retorqued to 55 FOOT pounds,the 5/16 bolts to about 18 Foot pounds, 3/8 to 25 FOOT pounds. Good Luck Lou Cote

bigboy308

Isn't there a difference in the output shaft and universal joint? Didn't Cadillac have an one-piece driveshaft and splines on the output shaft? I don't thiink a Hudson transmission has anything but a universal joint and a very short one at that. Using a two-piece driveshaft, the sliding splines are on the back shaft, not @ the transmission output shaft. I'll have to go to the shed tomorrow and take a look!

[Deleted User]

Let me know if you're gonna get rid of that 308. I may be interested.