Rear end swap...

[Ziptar]

OK, Long but, bear with me..

I have been doing some checking and it looks like swapping an TH350/700R4 front half onto the 79 Rear half might work. This is what I have found so far:

Front Half:

If I search car-part.com for 79 "4x2, 131.5" WB, AT, TH350, two-piece, front section" it brings up drivelines from 77 and up trucks. Some of the descriptions show some are from 700R4, short and long shaft TH350 trucks.

If I search for an 85 "4x2, 131.5" WB, two-piece, front section, AT, TH350" I get pretty much the same results. 77 up Listings for Long and Short Shaft TH350s and 700R4s.

If I Search for an 85 "4x2, 131.5" WB, two-piece, front section, AT, TH700" I get 82 Up results.

If I search on a 79 "4x2, 131.5" WB, AT, TH400, front section" I get 77 Up results all from TH400's.

Rear Half
Searching on an 85 "4x2, 131.5" WB, two-piece, rear section, AT" brings up 82 Up regardless of transmission.

Searching on a 79 "4x2, 131.5" WB, AT, TH350, two-piece, rear section" brings up 74-81. there is no mention of different 10 and 12 bolt rear at least not on the 131.5" WB.

Searching on a 79 "4x2, 131.5" WB, AT, TH400, rear section" Brings up 79-81 results. Again no mention of of 10 and 12 bolt rears on the long wheel base.

In looking at the comments in the descriptions about Weld to Weld Measurements in both the 79 TH350 and TH400 they both appear to be around 34".

So it would appear that all LWB trucks got 12 bolt rears only up to 1981?? At least that's what the interchange would suggest.

Based on that it would seem the rear driveshaft section interchange follows the 12 bolt being unavailable in the 2WD C-10 Starting in 82. The rear sections for the TH400 and TH350 12 Bolt rear could be the same.

It also looks like the Splines between the front and rear sections didn't change between 79 and 85.

So at the very least it looks like I could just use the Front half from a truck with a 82 up 700R4 or a 77 up TH350 with a 9" Tailshaft.

That may not work and what I'll need is a both pieces from a 77 up Long wheel base truck with that has a 9" tail TH350 and 12 Bolt rear.

Or at worst it just won't work at all.

I guess what I'll do is try find a front section that might work or front and rear pieces that might work and have them on hand when I swap tranny's if they work. Great.. if they don't then I'll guess I'll be swapping axles. I'll have to start checking the local U-Pull it's.

Anyone give me some input? The interchange can be wrong I know... Looking for real world experience.

Does anyone have a Pre-82 12 Bolt rear, 2 piece driveline TH350 8FT Bed 2WD 1/2 Ton Truck could get me a Weld to Weld measurement on the rear half to compare to the one in my 79?? That'd be awesome.

Thanks.