"Mid 60s baracuda 8 1/4"

I have a 70 Dart Swinger with the usual 7 1/4. I have an opportunity to buy an 8 1/4 from a guy who's telling me it came out of a mid 60s fish. For it to bolt up in my Dart it has to be from a second gen (67-69) barracuda right? Just trying to seperate fact from fiction.

The 8 1/4 didn't come out till the early '70s, so that was swapped into that Barracuda at some point. Gotta keep in mind these muscle era cars are 40-50+ years old and you never know what a previous owner has done in that time.

Just make sure it's 43" perch to perch and the overall width (with drums) should be around 57 1/4", otherwise it's not an A-body axle.