Floor Framing modification doghouse construction
Had to reconstruct the framing around the doghouse. We tied into existing framing where we could, see photos. They used square tubing in most cases we used the same gage tubing. The width of the Duramax is obviously wider but still fits when you modify the floor framing around the existing engine.
We also did have an issue with the floor above the transmission and had to make a transition plate with a slight bump in the floor. Did have to modify the cross member for the transmission. For transmission cooling we used an aftermarket cooler where the stock unit goes on the Duramax plus we plumbed a large unit under the floor with a thermostat fan controlled for additional cooling as we often pull a large car trailer with us.
The doghouse was a start over. We wanted something as lite as possible with good sound and thermal insulation. Since I do kiln glass work, I used kiln insulation, good up past 2500 degrees and great thermal resistance, that is the white batts in the photos. We also used a layer of silicon thermal barrier used by Nascar vehicles. We clad the framework with stainless steel as it does not conduct heat like normal steel. We put it in the MoHo and was pleased with the sound attenuating and no heat coming thru the doghouse. I am going to put some sound deadener on the outside as a further measure.
If I was going to do this again, I would not have done the GM dash as it added literally a hundred hours to the project and made the wiring overly difficult. If I would have kept the wiring with the engine when I bought it running on a pallet it would have saved me a lot of anguish. Ah the felling of 20 20 hindsight
1979 Airstream Motor Home