The van diesel engine and various other components would work for a pickup or Suburban installation. There may be a couple minor items that'll need to be changed, but overall, most accessory items would work fine. For example the oil dipstick, oil fill pipe, throttle & cruise cables are different between the two applications.

The gas big-block equipped Suburbans and trucks received the same larger radiator as the diesel - at least they were the same physical size, so I'd try it. If the Suburban was equipped with a 350 gas, it'll need another radiator.

A non-OD automatic worked just fine back in the days of the 55-mph speed limits - the first 9 years of my GM diesel experience was during the days of 55.... Nowadays, you just can't comfortably run at freeway speeds without an OD. Plus, when I upgraded to an OD automatic, I saw an immediate 6-mpg increase.

GM produced vacuum pumps and a VRV (Vacuum Regulator Valve), that was bolted to the side of the fuel injection pump, to simulate manifold vacuum on a gas engine. The VRV allowed a TH400 (or TH350) to function and shift normally behind a 6.2 diesel.

Jim