Your question is ambiguous. In the older la engines, there are several flywheels, depending on early A with the small wheel and housing, or trucks which are larger, and whether it is balanced neutural for a 273/ 18/ 340 or whether it is weighted for a 360LA. A 5.9 magnum IS WEIGHTED DIFFERENTLY than a 360 LA This means you cannot use a 360LA weighted flywheel on either 5.2/ 5.9 magnum