The 390 4spd idea is fine but a 302/289 C-4 setup fits with such a minimal amount of modifcation. So much easier than a Vega V8 change out it ain't even funny. Not only that but the Pinto is a much more solid unit to start with therefore requiring much less extra bracing if one wants the project to outlive the motor. The Gremlin (which I have not as yet had the opportunity to own) being a bobbed Hornet was designed stout enough for a V8 from the get-go. The biggest factor really on the Pinto conversion is to start with a " 71 or ' 72 because the steering column has a section at the box end that is a large dia. flexible cable essentially. With just a small amount of pesuading with a deadblow mallet in the tranny tunnel the motor and trans can be pushed back just enough to provide clearance. This is not anything like as easy with a 390. You do however have clearance for launch! DANA aka orphanautos