73 Duster

A 351 Cleveland is another option, but the Windsor is a more common motor, produced until 1996, I'd think a 429/460 would be a fairly tight fit, and can be pretty costly to build. 390/428 would be harder to find, and likely very expensive to build. The 351W was available in the 69 Torino/Fairlane line in 1969, another reason I would give serious consideration that motor.