Best chassis for crewcab shortbed

[409fanatic]

I have just purchased a wrecked 87 Crewcab Dually that I want to build into a shortbed crewcab. The dually chasis is trashed beyond repair, I have 2 running truck to choose a chassis conversion from. I have a 2003 Express 2500 Van with a 4.8L V8 and a 1995 Chevy c1500 Extended cab with a 5.7L V8. Which of these will be a simpler swap for my project? My plan is to have a standard size shortbed on the crewcab, but have it short in front of the rear wheels like the modern crewcab trucks.
Any thoughts and suggestions welcome.