Swapping Advice for 700R4 or 4L80E

[Fletch79]

'79 K5, 400SB, TH350, NP203, GM 10-Bolt front and GM 12-Bolt rear.

I want the overdrive gear.

What's involved in the swap?
Do I have to change T-cases? Driveshafts?
Need Adaptors?

How tough is it to get the E-trans to run right in an old truck?

Thanks Folks,
Fletch.

 

[84_Chevy_K10]

You will need trans, a 208, 205, or 241 case and whatever it takes to mate them together, driveshafts, and a crossmember. You'll want to wire the tcc lockup too with either a kit or make your own from schematics that can be found online.

I have never seen a 700 bolted to a 203 although I'm sure it could be done with the correct adapter as a TH 350 and 700R4 share the same spline count output.

I can't see trying to keep the NP 203 though, it's heavy and still chain driven and the low range sucks compared to the lightweight aluminum cases. Unfortnately though, the 1-208 and 241 are both slip yoke rear output. The 241 can have a SYE installed though. 241s are kinda tough to find, but on here you can find anything.

Ask any more specific questions after doing a search and we'll help you out.

 

[arq]

advanced adapters makes an output shaft for the 700r to mate it witha np205, if it works witha 205 it will work witha 203.

ARQ.

 

[73K5Kid]

The advance adapter output shaft will also work with the 203. You can use the shaft for both. I am running a 203. If you have any questions with the swap pm me. I just did the swap with a little help /forums/images/graemlins/grin.gif