Matt, I have a 72 with a ' 401 ' in it and I have to tell you that if you plan to put the car on the road for street drivin', the tube type aftermarket headers will hang very low to the ground. You will have about 2-1/2 to 3" of clearence. I had a set of HOOKER headers on my car and with the dual exhaust system, I was bottoming out on pot holes and dips in the road. When I ripped the flange off, ( pot hole ) I went back to the stock ' 401 ' cast iron headers and solved many problems. The dog-leg ports of the ' 401 ' headers flow almost as well as the tube type, and you won't have to worry about bottoming out! Also, headers will hit the steering box and dent the hell out of them! I had to put a chain from the block to the frame to keep the motor from pullin' up, LOT'S of TORQUE !!! Well, that's i't, I hope my info was useful!