This sound like an interesting project, can you post a picture of the Panel Truck? It sounds like you will put the wheelchair lift in the back door, why not front door? I have no idea how it would fit.
You might be able to find a used 235 that someone no longer needs. Someone that swapped in a 350 and has that old running when pulled last year 235 sitting under a tarp in the yard, ahem…


1947.2 Chevy Panel Truck 1-ton
In Project Journals
In the DITY Gallery
1955.2 Chevy Suburban
1955.2 Chevy 6700 Bus/RV