Yes, I have changed the seal in my Challenger with headers.

Did NOT remove anything, poped the seal out with a screw driver going in at an angle and taped the new one in with a small hammer

Tom ,

2011 Ram 3500 C&C Diesel
2009 Challenger R/T
1971 Challenger Conv. 511/4 speed
1970 Challenger R/T 503/727