xracerbob Bob I am running this manifold for 8 years on my 452 motor. I did have to do some cleanup work on the pushrod holes and coolant passages. With the FI system the car runs great with go power and a flat tork and HP curve. I am running a 501-533 cam. Shelby block and heads. 368 hp and 460 tork. 1,200 cfm throttle body on the top. You might want to go the the FE-Forumn. There is a guy, Joe Craine that will match the ports on most manifolds. Matching the runners helps. 30-40 cfm readings in differents between ports. Side note, It took 10 months to get manifold
No other problems. Make sure you check all the pushrod holes for clearance through the whole travel of the pushrod. Rick L