[Bdb68]

Originally Posted by 70custom20

Great build, thanks for sharing. I’d love to do a diesel swap into my ‘70 K20 someday. A couple of questions if you don’t mind? In your opinion, what are the pros and cons of using the Duramax engine vs. the Cummins engine? Is there a transfer case adapter for a new process 205 that will bolt onto the Allison transmission? Or is there a bellhousing that will bolt to the back of the Duramax to allow the use of an NV4500 transmission? I’d like to try to plan out my build as much as possible, like you said, if you plan ahead, you can save money.

70custom20, Thanks for the comment. I have done several LS swaps which were a lot easier, if you just want modern convenience and fuel economy, however the pulling power and unique wow factor me makes it well worth the work to me. I have a 96 Cummins 12 valve I will be swapping into a square body when I get all the bugs worked out on this truck, so until then I don't know all the pros and cons. Here is what I can tell you about my experience. The Duramax physically fits well into the 68, I only had to do minor trimming of the frame. The trans and transfer case fit with the high hump and some sledge hammer work to the bottom of the floor. Don't be afraid of the wiring and computers, I sent my harness to Ken from Standaloneharness.com, he cut it down only like 3 wires to make it fire up. It really wasn't too hard, read a lot, trail and error and good fab skills (or a buddy who is a fabricator and welder really helps). As far as the trans adapter I follow a company called Precision Fabrication Plus, Inc who make swap parts and kits to put a Duramax into square body Chevys. They make an adapter to bolt a NP205 to an Allison or ZF6 manual trans. I have never ordered from them so I can't comment on quality or service but they have some cool products. As far as NV4500 swap behind a Dmax, I have no info on the subject, however I follow a guy on Instagram who swapped a Duramax and ZF6 trans into a 71-72 and it seems to be working well for him. Hope that helps.