There are kits available to mount the engine and trans. Downsides are 4 lug front end, rear end, and the availablity of parts to convert. Monza used to be the answer, try finding a parts car today. Rust, especially around the windshield and quarter panels, is bad.
Plus side, they are light, you don't need to get crazy to have a quick car. A good roll cage will tighten up the sub frame, I like the wagons, they seem to work better for the strip.
There are a few guys here that have Vegas, do a search to see what they came up with. I haven't seen a Vega outside of the strip for quite a long time. This is in Cal and you just don't see them.
"When I was younger, I could remember anything, whether it had happened or not." - Mark Twain