I won these off of eBay last week and decided to go Pro Street with one of them, something I've wanted to do since the '80's. I chose to use the AMT Pro Street '66 Nova kit because it's the closest in size to the Vega.
I had to trim the sides back to fit. I glued the sides onto opposite sides and cut off the excess.
The Nova chassis is 1/2 inch too long, so I cut that down too.
It fits. Now I need to think about what to do next.