http://www.ramclutches.com/clutch%20u/cl_u_1.htm
I have a C30 402 (now 413) w/ a 12" Borg & Beck clutch. Yes; B & B assy's were generally installed in the larger work trucks. They have tenacious holding power. Anytime the clutch is changed, the flywheel (if it's still servicable) should be turned as well.
I started with this article. Any misalignment whatsoever will make a mess of everything including the flywheel surface. It sounds like that's the problem you have.
The clutch shouldn't be as difficult as you're saying. Clutches were the connection long before A/T's. As a matter of fact, you can always modify w/ an hydraulic clutch if you really want to tinker with it.