v-6 in early A-body

V6 isn't a bad idea at all. My research leans toward a 3.9L being more simple overall, especially in terms of rwd transmissions since it's more "smallblock-like".

I'm in process of putting a 2013 3.6L pentastar in my 72 Swinger. The Pentastar is a wide and tall engine and I think it would have a hard time fitting in an early A-body.