68 K10 swap Manual to Auto - Help

[Doogiew]

Hello everyone - looking for advice to swap out my Muncie SM465 4 speed for a 700R4 Auto. Many questions:

Can I keep my existing transfer case and drive shafts?
any special bracket needed?

Thanks for any help you can provide!

[obijuan]

Id avoid the trans swap where you change the output shaft in the trans. Use the spacer instead and that keeps the front driveshaft from hitting the trans pan.

[Doogiew]

thanks that is good to know!

[obijuan]

Originally Posted by Doogiew

thanks that is good to know!

Also, you'll need a th 350 to 205 adapter as well as the 27 spline input gear to put into your np205 case. Requires disassembly. Driveshafts will likely not work as is. Maybe you could get away with a bolt in from the same truck the front shaft came from.

[andrewmp6]

Do you know what t case you have now?

[Doogiew]

I am not sure what transfer case I have - here is a couple pictures of it.

[Bigdav160]

Rockwell 221. I'm not sure if it ever came with an automatic in front of it.

[Doogiew]

Thanks for the help!

[andrewmp6]

Its a rockwell and the bad news no one makes any replacement parts for it or even a swap adapter for it.The cheapest way would be a 700r4 with a np208 or np241 on it.You would have to have no driveshafts made for that.Next step up is 700r4 with a np205 swapped on it with a adapter kit.And that would probably need new driveshafts also.

[dennislbrooks]

I used a np208 with a 27 spline input shaft for a 350 turbo or a 700r4 in my 67. I think the output is 32 and will be a slip yoke. Mine will have a 700r4 one of these days.

[msgross]

I'd focus on finding a full setup out of a donor truck, to include the crossmember. You'll want a newer Transfer case as stated anyways. Worse case scenario is that you have to have a driveshaft cut or made but you'll be happier in the end with the right tranny. Right now it looks like you have the original Rockwell T221 transfer case and SM465 transmission, I assume with a Lo 1st gear (granny gear).

If you weren't worried about overdrive you could go with anything from the 70's.

[Doogiew]

Thanks I do want to find something out of a newer truck with overdrive, any ideas what transmission / transfer case combos would work. I don't mind getting the driveshaft modified. It would be nice to know what years of new chev trucks would fit and then buy a complete package from a donor truck.

[msgross]

Originally Posted by Doogiew

Thanks I do want to find something out of a newer truck with overdrive, any ideas what transmission / transfer case combos would work. I don't mind getting the driveshaft modified. It would be nice to know what years of new chev trucks would fit and then buy a complete package from a donor truck.

This page will show you a lot of the options, pretty much 73-87 should yield a lot of options. Any solid axle truck is a start, learn what the tranny looks like.
http://www.chuckschevytruckpages.com/73-87specs.html

Here's an example near me... http://lancaster.craigslist.org/cto/5492792276.html

87 K-20 Suburban
Engine: 5.7L (350) fuel-injected V8
Transmission: 700R4 automatic with overdrive
Transfer case: NP208
Brand new 4" Rough Country lift kit with dual steering stabilizer and extended brake lines
Wheels: American Racing 16" (blacked out) with 285/75/16 BF Goodrich All-Terrain tires (good condition, will pass PA inspection, about half tread left)
New dual exhaust with Flowmaster mufflers, and Hooker full-length headers