Reversing some"custom modifications"with limited skills....

A couple of years back I bought a couple of cars from a guy that just wanted to get out of the hobby. Both of the cars were Dart Sports. The first car was a 74 with a slant six and drum brakes. This dude was rusty and incomplete so it was stripped down and scrapped.
The second car is an actual 340 car, but it has had a checkered past...