70 72 duster driveshaftsthe same wheter a 4 speed or auto?

No the driveshaft from a 727 automatic will not be the correct length for a 4 speed A-body car. It will be too short.

If you have a driveshaft from a duster that had a 904 automatic and a 8.75" rear it will fit a car with an A-body 833 manual trans and an 8.75" rear.

The 904 auto and the A-body 4speed are the same length.

THE 727 Transmission is longer than the 4-speed transmission.

Bob