I have a 3.5" diameter aluminum driveshaft from a parts-car I purchased.
The car had a th350 and stock 10 bolt. I believe this will fit all 82-02 th350 swap cars, but please measure to make sure.
The driveshaft has a spicer yoke, and measures 44.5" from center of u-joint to center of u-joint
Pick it up in Springfield for 125.00 obo
Save some money and get a nice custom piece.