I am not up on them myself, but I do know, I bought a 74, back in 81. Bone stock, paid $1800 for it, but it was in great shape.IN and out was a high 9. Had to replace the generator, the heat exchanges, and a set of tires, other than oil changes, that was it for near 3 years. Got a kick out of watching my Dad drive it though, he never did find reverse! Great in the snow(fun) with a set of mud tires. Not as good as you would think on fuel, but not terrible, mostly depends on how it's driven.
Now for the Vega, cut the two 1/4 plates of the motor mounts, slide a Buick V-6 in there along with a Turbo 350, or a Powerglide, and you had an instant Hotrod!