My Grandpa put a 12 Valve in a 86 Chevy because Dodge couldn't give him the exact truck he wanted. He put the SM 465 Behind it with a Browning mechanical shift two speed underdrive behind that to a Dana 70. He extended the frame I think Nine inches to put a A bigger flatbed on. He hooked it up to our old 14X70 Trailer house to move it out of the way Three hundred yards I think but it was a Pickup that pulled it. I am also pretty sure that he kept the front spring setup exactly the same. It was a Frankenstein truck. He used parts from every Manufacturer to do his build which was his decision becasue he knew what would work the best so he at one time kept a list of all that he had done but I am pretty sure that is all gone now. The point was with the Cummins the splitter the 465 he could always keep it in the power range and flawlessly do 90-100 miles per hour. This was an absolutely amazing Truck I will try to get some more specs on it tomorrow but A real built truck engineered by an old school trucker that had every single aspect of what those of us who haul big loads would really wish to have in a tow vehicle / daily driver