That all depends on what you consider easy and also which year 454 you have. BBC's i believe use a 2 piece rear main seal up until 1991 and then starting in 1992 GM went with the 1 piece rear main seal. I prefer changing the 1 piece rear main seal but that entails pulling tranny/T-case backwards in order to do this. The 2 piece rear main entails dropping the oil pan and then trying to fish the upper half of the seal out of the block which isn't too much trouble but in my experience is harder to do than pulling the tranny/Tcase backwards to change the 1 piece seal.