So I was thinking of fabricating a set to go on my '81 D150 as it has severe traction issues since I took the box off of it.

Anyone have any experience with either the CalTrac style (U-bolt to front eyelet) or tracbar (Welded bar to axle itself and frame)?

We had a 68 d100 we built for racing a few years back. Save yourself the money and go strait to a 4 link. These trucks have horrid traction issues, box on or box off. They are like the supra of the truck world. Long box trucks are about impossible to deal with...

Thanks that actually helps me a fair bit as that was my next question.

Not a problem. Check out http://www.sweptline.org/forums/

They wont cover your 81 directly there, however, the traction issues are very similar between the trucks discussed on there and yours you currently own. Goodluck!

Thank you very much sir.