Ya, I hummed and hawed a lot about the strength of the Borg Warner T5 that they put into astros camaros jeeps and mustangs. Theres a wide variety of models of T5, and thats a pretty impressive list of names who have used the T5 in their autos. So, Because I'm sticking with the economical 4.3, and I'm not gonna be a bushwhacker, I just wanna go fishin and stuff, I'm gonna go with the T5, but I read up abit about what makes them weak and what the different models are. I decided to use an original "Astro" T5 tranny. I just changed the output shaft and tailhousing from an S10 4x4 onto it. The S10 T5 had a lower gear ratio than the astro, but that in turn makes them even weaker. So I stuck with the Astro Gears.
If I wanted to put a 5 speed-V8 in a 2wd Van, I would defiantly look for an 89-92 or so Camaro with a TPI-v8-5speed. That trans shifter position is way to far aft, but will fit an astrovan perfectly, if you can swap a tailhousing from an "Original" astro T5.
Oh hey, and I have one left over from my swap to 4wd. Guess what my next project will be...
For a tuffer V8 4x4 astro van, A chevy truck Trans like an NV3500 or NV4500 or even a granny low T-18 4 speed could work.
I didnt look into it a lot to see what kind of clutch linkage is used etc on those tuffer boxes, but you wouldnt be thinking about it if you werent gonna have to Make it fit right?
Good luck whatever you decide to use, and have fun !