B body HP exhaust manifolds in A body

Drivers site the flange is turned different from early to late . I used 71 manifolds and cut the column so it was flush with the Firewall . My 69 RR manifolds the flange hit the column shaft. The 71 Super Bee cleared. I also used the biscuit mounts from a Dodge truck they were thicker and lifted the motor. I installed a 383 440 is taller so things will be different with height.