There are plenty of places that list what the different T5's are. Please look at one carefully.
Good gear ratios were available in both NWC and WC, look at the list...
Camaros started using the WC version in '88.
S10 started in '93.
They started using the Ford pattern in '93 on everything, as far as I know. I think they started using it earlier than that in Astro vans, but not sure.
83-87ish is where you will find the S10 versions with mechanical speedo, but not all are, so you need to put your eyeballs on one before you buy it. Same for Astro vans.
Basic rule for T5's,
Always see it before you buy it, and know what you're looking for, ie bolt pattern, speedo type,shifter position...
