The 2 biggest issues I see will be oil pan clearance for the AWD, and the intake/aspiration. IIRC 91 V8s were TBI, the 01 4.3 wasn't. It's PROBABLY just an issue of installing the proper intake and injection system on the V8 and changing the chip, but don't quote me on that.
The LS designation on our vans designates the Luxury Sport trim level. The LS engine was never a factory option for the Astro/Safari line.
Here's the thread for my 95 V8 swap. It's long winded, but I tried to post pics, part numbers, and sources along the way.
It's 2:00 AM, and I just read through the first 10 pages in the V8 forum. Nothing I read seemed to clarify my thought process. I found a complete van at PnP toda... yesterday. It's is a 1995 G20 conversion van. PnP got it from an auction here: (expired link removed) I noticed it has TBI, my 95...