95, or 96+? Vortec 350 swaps are easy as shit in those if they're 96+. Get a
reprogrammed ECU (or a 411 LS1 box the trucks used em too) run a few wires/rewire for the 8 cylinder FI connector, extend a few shorties and you'd probably be good to go. The accessories etc. move over. Use the V8 swap mounts for about 70 bucks a pair, and some G-body headers (Hedman 68600 are dirt common and fit well.) Slap a cam in there and have some fun.
That being said though, what Camaro calipers actually work on these? They are B-body/C1500 calipers, at least on the older ones. The calipers a typical Camaro/G-body/S10 use are TINY compared to the Astro's. Just saying. Upgrades could come in the form of front/rear 6 lug though, which would be the 03-05 models.
I like mine, they are fucking handy to have. It's been in hibernation and I seriously the fuck miss having the cargo capacity. It's handy for everything from grabbing some stuff for home improvements to getting rid of that pile of junk that's been laying around for eons. Eventual goals are a 4L80E, redo the 9", a 2 or 3" rear drop (the silver one is at least a 2 front 3 rear drop) to level it out and some form of boost. The TPI engine makes it a hell of a lot more fun than stock, but isn't exactly a power house in the age of easy 400+ HP factory stock cars.