This is the correct year 6.3 to buy. In 1971 the new ones had air pollution control equipment and I understand were slower. I had a 70 6.3 from 1973 until 1984. When I sold it it was in perfect shape, 150k miles, not a scratch or dent or any rust at all on the entire car, and the silver paint was brilliant and perfect (repainted twice over the period at a cost of about $3k each time). Sold it because I was spending at least $500 per month on maintenance. Was never happy with the air suspension.

But it was some car.