Lots of issues to deal with using Astro van parts. The steering system would have to be re-engineered to allow for a more correct steering box shaft angle, plus you have to deal with the wear prone dual idler arm setup. The entire drivetrain is offset to the right by about 4", whch can cause problems with the riveshaft angle, unless you use the van rearend, too. On the engine, you would need a different intake manifold, as well as a non-comutor distributor, but it can be made to work. That part would actually be the easy part.
I won't say it can't be done, but it will be alot of work. I'd put it at a 8.5-9.5 on the scale.
