The corvair? I’d like to check that out. I have only seen pics, but never in person. I read about one guy that did a 454 and couldn’t keep the front end down. 
The jag conversion is supposed to handle a lot better than stock, too. It takes about 100 lb off of the front end compared to the v12.
Does anyone have a link to that model A or model T swap with the turbo 4 cyl? It looked completely stock and even had a misfire programmed in so it sounded stock cruising around. That was the coolest swap ever.