Welcome to FTE 89! I have to agree, I notice big front end changes between 91 and 92, but when you tear it all down, not much did change. Interior did change quite a bit on these trucks too. Radio and climate control swapped places, and the dash changed quite a bit!

 

Most of those changes are cosmetic. The basic underpinnings are very very similar between 91 and 92, where quite a bit changed between 86 and 87.

 

I agree EPNCSU. I've put a newer style (94) front end onto a 90, and with some slight mods, it all fit together. But like you said, the changes from those years were mostly cosmetic.

 

With minor work you could put the 1980 cab on a 1996 frame. About the worst of it would be the wiring. The chassis didn't change from '80 to '96 that's why they are all in here. I still remember when the full size vans didn't have a forum of their own.