340 4 speed vs 5.2 5 speed

U say u want mileage , but yet ur going with 3.55s or 3.91s. Then for sure u need the od tranny. But ur still in a dream world with ur lil 318 if u think ur even gonna be close to a 340 or 360/5.9. Kim
I don't think it's a dream, 5.2 has bunch of potential everyone always writes these off .