I think whatever fits an a-body will fit an early b-body
On 1967 to 1973 A bodies with hemi motors with the tranny mount in the stock A body locations, I've swap more than one set of Hooker chassis headers between those cars and the 1966 to 1971 B and E bodies
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
On 1967 to 1973 A bodies with hemi motors with the tranny mount in the stock A body locations, I've swap more than one set of Hooker chassis headers between those cars and the 1966 to 1971 B and E bodies 
