TX WTB Two-Piece driveshaft SWB TH400

[TravisMartin]

I have a 1978 SWB big block with TH400 & 3.73 12bolt; driveshaft has been lost by previous owner. I'd like to find a correct replacement. I will be retrofitting a 4L80E so will be shortening it.

Question: would the shaft from a long wheelbase truck work; that is, is the length of the rear section from the carrier bearing to the differential the same SWB and LWB, or is the front section the same, or are they both different? In other words, could I use a LWB setup since I'll be shortening the front section for the 4L80E anyway? (trying to open up the possibilities of someone having what I need...)

Thanks!