I have a 73 Mach 1with a 351 Cleveland and have successfully installed a ram air with the Petronix Billet Distributor installed. I have a Summit 750 CFM carb installed with the edelbrock 2750 performer intake. As I already suspected and this forum stated fitment would be a problem since the Petronix Billet distributor is about an inch higher than stock. I installed the air cleaner assembly and marked the air cleaner to start cutting. After cutting the assembly with a Dremel tool, I took some cardboard to make the shape required to seal the air cleaner. I used some spare sheet metal and tack welded it into place and afterwards it fit perfect. I did have to use the alternate method for the ram air rubber seal to make the hood close properly as suggested by Tony Muscle here: https://7173mustangs.com/threads/looking-for-alternative-ram-air-plenum-seal.40780/ and it fit great.