Good luck. My 71 Cougar has 351 4V with hooker super comp headers and C6. I had to dent the larger deep sump oil pan for the headers to even fit. Most likely you'll need to drop the headers. Probably spend more time trying to snake the trans out than just unbolting the headers and pulling them out. If I also remember correctly I had to jack the front end a mile high to get one side out.