Year to year /6 compatibility

Been driving Valiants and other Mopars with slants in them since the 60's.I like the pre 1967 motors but that's just me.The 70's motors are good as long as you lose all the pollution control stuff and put on an early carb. That wakes them right up.Any year will fit in your truck especially seeing that it's a standard shift vehicle.I wouldn't use anything later than a 78