americastire has a pretty decent tool on their website that can help, if you know the year and model the rims are from. One the home page it will ask for year/ make/ model, then select show wheels. Then do the same for your van and compare... done.

 

Should be fine as long as they are the GM rim. Most offsets and back spacing are pretty much the same between the vans and the trucks. My '04 is running the GM truck rims right from the factory.
Mark

 

Yes they will fit My last Astro I have 78 chevy 2 wheel drive rally wheels on it. link takes you to a picture of the wheels I had.

http://www.partsgeek.com/5mcxdtx-chevro ... olet+Wheel