What was the ultimate "normal production" factory A Body?

I had a 1976 duster with a super /6 Two barrel three speed on the column, I pulled loaded farm wagons with this thing. One winter the rad froze and the temp spiked, I was young and didn't give to ***** about winterizing, pushed it in the garage, chalked up the wood stove, drained, poured fresh anti freeze without doing anything else and it ran better! might not be the fastest, but tough it was