We are embarking on changing our gas big block Airstream 1979 motorhome to 6.6 Duramax Allison. I am sure I will have a lot of ignorant questions as I go thru this process. We are fabricators and metal workers so that part is within our skill sets. I have a running engine and transmission being delivered to me in a week or so. It is suppose to be ready to plug in with necessary wiring changes to run alone on pallet which I receive it. A few questions that I already know I have to solve are as follows:
1. How so I hook up the cable shift linkage to a steering column from a turbo 400 existing to new Allison. Do I have install the donor steering column also or what.
2. Power steering, will the pump off the Duramax be compatible with older GM system have not checked the pressures yet.
3. I am suppose to get all the radiators, coolers and intercoolers. Any hints here would be helpful.
4. Will the motor mounts on the Big block fit the Duramax or do I need a kit for conversion of motor mounts?
5. The weight seems to be close so I see little issues that side of it.

6. The most difficult part is I have to smog this unit when I get it done. I have talked to the California Smog Referee. Actually called me the person who will be doing the inspection. The only issue he sees is I need a letter from GM Dealer that the engine I am putting in would be an engine they would put in a similar vehicle today. Crazy idea but the MoHo I have is a light truck chassis (P30) and this may work just need a dealer who would write a letter saying this. Open for ideas here.

7. I was going to put an aftermarket air kit since the engine compartment is tight and I will have to fabricate a new engine cover for sure. I am sure this will work out, maybe similar to the KN units or recommendations.

I will post photos of our progress and hope to get started next week with disassembly and getting a plan in process