all I have to say is when buying an old car dont trust anyone about its history

I know that my 76 Pontiac Ventura is an original low mileage car, verified through documentation when I bought it in 2011, plus the overall condition of it was such that it was clear that it had 27k miles, still had the original tires on it! It doesn't get driven much, currently there is around 41k miles on the clock. I have tried to sell it a couple of times but it seems like nobody wants a Ventura, if it were a Nova, it would have been sold long ago.
Now I am starting to think that I should just do what I want to with it and forget the "originality" since it doesn't seem to matter much anyway. Hey, it's never been in a crash, and has absolutely no rust on it, so what better way to start than skipping the body and paint expense?
I did have it painted about 7 years ago and it still looks great.
I am merely curious. Does your Ventura have the Chevy 307, or the Buick 350? Or is it the chevy straight six?
I had a early 70s Omega that still had the Olds engine. Anybody that wanted to buy it was hoping for a chevy, so they could swap their "badass" chevy into it.