Mine is a '67 coupe with a '72 Pontiac worked 350 engine. My problem is the Pitman Arm. The car was originally a 6 cylinder; I dropped the 350 in 20 years ago. I recently installed headers, and the 6 cylinder (straight) Pitman Arm is hitting the drivers side header on hard right turns. I purchased the 8 cylinder Pitman Arm which will solve the problem since it is crescent shaped, to avoid contact with the exhaust mainfold (header). The problem is the diameter of the end that mounts to the steering box; it is approximately 1.15 inches, as the current steering box only has a 3/4 inch mounting shaft. If I locate an original 8 cylinder power steering box, will that solve the problem? Has anyone else done this conversion? Any suggestions? The Pitman arm did hit the stock mainfold but it really was not an issue; the header is getting crushed. Thanks.