It's been months now since an update, so here's where I am with my 39 Chevy COE project.
The P30 frame is great. I have the front air bags in & holding air. I found a Ford 1 ton dully rear end with 354 gears. I boxed & C notched the rear frame so the frame will be level when air bags are empty. I shortened the frame & I have a 4 link rear suspension with air bags in place. All on 16" dully wheels with 215/60R16" tires. The small tires look rear good in the front fenders. I sat a small block 305 Chev. motor & a 700R 4 speed trans in the frame for mock up. The motor is sitting far back under the cab & lowered enough to be under the floor even though the cab is about 6" lower to the frame than originally. There will be a short doghouse between or under the seat for the carb & distributor, depending whether I decide on a bench seat or buckets? I am making it a tilt cab. So I have the cab sitting on a sub frame, much lower than the original stilts the cab sat on originally. So far, so good. That's were it sits now.
I found a set of Freightliner tilt cab hydraulic rams & cab jack, so now it is time to add hinges to the sub frame & get the cab to tilt. I have a long way to go, but it is starting to look like everything is going to work out.
As of now the running boards sit 3" off the ground, but I can see were I will get two more inched lower. I plan on having it sit 1" off the ground when bags are empty, just for safety. around 6to7" driving height.
..........some day..............