Hey Joe, Your beautiful truck is one I really admire! I like the fact that you stayed with an L6, too, but you didn't exactly leave it stock! ;} I have only done the 235 to 250 swap once, but we used 2x2" steel tubing and some 3/16" plate for the front mounts. From the time we set the engine on the rear mounts, using the bellhousing that came on the engine, it took about 2 hours to cut and weld up the mounts. We used a fan shroud from a 350 attached to the back or the Harrison rad with zip ties. It is a pretty simple process, but it does require basic fabrication tools and skills.
best wishes,
Les
