1955 Chevy truck need help with transmission mount!

[samples45]

Hey guys! I thought I would post here instead of my thread figured more people would see it. I'm putting a 700r4 trans in my truck it's out of a 90 vette as is the motor. But the transmission doesn't have holes in the bottom for mounting.. Any advice would be great!

[samples45]

Sorry for the sideways picture!

[OrrieG]

Are we looking at the top of the trans tailshaft? Not familiar with Vette mounts.

[samples45]

Originally Posted by OrrieG

Are we looking at the top of the trans tailshaft? Not familiar with Vette mounts.

Yes, those grooves you see is the passenger side of the tailshaft. There is no transmission mount, it's a tourqe bar but I'm wanting to use the just a mount with crossmember

[tmoble]

you'll need to change out the extension housing AFAIK. I believe any regular TH350 housing will work. Does it have a traditional speedo cable drive spud now?

[samples45]

Originally Posted by tmoble

you'll need to change out the extension housing AFAIK. I believe any regular TH350 housing will work. Does it have a traditional speedo cable drive spud now?

no its electronic..im wanting to go with the old school cable style

[tmoble]

older style housing won't fix that, there's no gear on the tailshaft to drive the gear on the cable. Apparently you have to change the output shaft of the tranny to be able to run the old style gear deal. The speedo drive gear is changeable on the TH350/700R4 but IIRC correctly they changed the shaft somehow so the speedo gear won't fit. I'm not a tranny guy and I could have some of this wrong. Might want to google around on it awhile. It'll be worth your time if you can find something as the electric units that accept the signal from the modern trans and run a motor to turn a speedo cable are not cheap at all. $400 and up last I looked.

I just bought an aftermarket dash unit to get around this deal. Also, my original Temp gauge was hinky and the old setup has a series ammeter, no good with a 100+ amp alternator and my original speedo just bit the dust a couple weeks ago.

[Speedbumpauto]

Would appear to me you could fabricate a piece of channel to take advantage of the holes in the sides of the tail shaft. You could drill and captive nut the bottom of the channel to accept a standard trans mount. It might end up being a little taller than stock but you could adjust when you do the trans cross member. Also, once you go to an electronic speedo, you'll never look back. A little expensive but, different gear, different tires, no problem. Two minute re-calibration and you're done.

[Rustoholic55]

You could make an aluminum channel the accepts the standard trans mount. Remove the tail, and weld the channel to it.