th350 Transmission & 250 Inline 6

[whutdidyousay]

First post on this site.......I just bought a '70 rust bucket with a 250 inline six and a th350 Automatic trans. The trans is shot, Slips alot and takes 20 seconds to engage gear.

My question is.... Do I need a special version of the TH350 for a 6 cylinder or are they all the same? I will be putting a used one in there off of Craigslist while I take my time and get the parts, tools, books, and videos to rebuild the trans that is in it. Everyone I know says I can handle it.

Also what are the dimensions of the tail shaft? Basicaly how do I tell if I have short or long?

Thanks!

[Tx Firefighter]

The Th350s from V8s are the same. They will freely interchange.

There are three lengths of Th350 trans, the 6 inch, 9 inch and 12 inch. You measure the tailhousing. It's the cone on the back of the trans that bolts on with 4 bolts. Just measure the length of your current one and make sure your replacement trans has the same length so you don't have to modify your driveshaft.

I will answer your next question before you ask it. The mainshaft inside the trans has to be changed along with the tailhousing, so you can't just swap the correct length housing onto the other trans if it's a different length.

[whutdidyousay]

Thanks alot for the speedy reply.

I did already know to make sure they were the same tail housing because it is a very complicated ordeal to change it.... Thanks for the heads up though.

Nice to know they swap out. Takes a load off of my research.... All I need is a tape measure with me now.

It seems that I've done just about everything mechanicaly to these old trucks except rebuild an automatic transmission.... guess there is a first time for everything.

Anyone wanna place a bet now on if my first attampt works or not?....lol