Transmission selection troubles

[hossnat]

Hello. I have a 68 C 10 that originally had a strait 6 and three on tree. I am putting in a big block and auto. Question is what auto to use? I think im set on a 400 but just dont know whether long tail or short. I have to consider the driveshaft loop and whether to use a two piece shaft or not. Want to keep it looking as stock as possible. Going to use original 12 bolt rear. Any 2cents would be greatly appreciated!!

[dsy1]

Are you sure you don't want overdrive? Dimensions of the 2004R are about the same.

[hossnat]

I'm not sure really. Have heard stories about the 700 and 200. Had a 200 in my 87 grand national and wasn't really impressed. When you say dimensions are the same are you referring get to long or short tail? I'm assuming shore tail. I think for what I'm looking for and the application the 400 is a safe bet for reliability and longevity. So it remains, am I looking for a long or short tail? I definitely don't want to have problems with the driveshaft loop. And BTW it is a swb stepside.

[Eddie H.]

My 69 came from the factory with a short tail 400 and a 2 piece drive shaft. (It's a longbed. You may need a 1 piece with a shortbed, I don't know for sure.)
I thought about installing an overdrive, but I really like the TH400. It's pretty much indestructable. It has lasted 47 years, spending most of its life on the farm hauling hay and pulling overloaded trailers out of muddy fields without any problems.

[firedemon]

I have a long tail theres no issues with a 2 piece driveshaft or the carrier bearing support . either will work fine

[LockDoc]

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I had a TH400 behind the 454 in my White '67 SWB. I wasn't happy with the 3.73 rear gears but it made all the difference in the world when I put the 3.07 rear under it. The big block had no trouble pulling that high of gear and it ran good on the highway.

LockDoc

[LongBox]

Both my (Ford) Mustang and my 98 Silverado have aluminum one-piece driveshafts. They are simple, light, and trouble free. I'd see if you can go this route.

[hossnat]

Thanks for the replies. We are definitely getting somewhere. So far I think I want a short tail th 400 and I'm thinking of a driveshaft. On a swb truck I don't know if it used the two piece shaft or not. If I use the short tail 400 can I use a one piece shaft and clear that factory loop?

[brihorse]

I have a 454 with a th350 and .411 gear. Motor came out of a 1975 pickup. I get 6 mpg. Turning 2850 rpms at 55 mph. I so wish I could get 10 mpg out of it. I have to fill up every 100 miles or so.

[haysonj]

Originally Posted by brihorse

I have a 454 with a th350 and .411 gear. Motor came out of a 1975 pickup. I get 6 mpg. Turning 2850 rpms at 55 mph. I so wish I could get 10 mpg out of it. I have to fill up every 100 miles or so.

Put a Gear Vendor behind it I have a 383 with a T400, GV and 410 rear with 35 inch tires and I get around 11 MPG around town and 14 on the highway

[hossnat]

Dang. I guess you could start by putting in a different gear. I'm gonna go with 307 because of the 400. No OD. I just need to figure out if I can use a one piece drive shaft with the short tail tyranny with out hitting the loop under there. Or do I need to use the two piece shaft?? I dunno.