Hi, i have a 77 425 motor and i need a rear main seal installed. my mechanic wants to know if he can get to it without removing the motor. he also wants to know if its a one piece or three piece???? he also wantsto know if he needs to drop the cam....these are all his questions...basically, how tough of a job is it and exactly what is the best way of doing it without removing the block. thanks much.

It's a two piece seal. You can remove it by removing the oil pan and the last main bearing cap. I changed the rear main seal on my 472 last summer. It hasn't leaked since!

great. thanks, any idea as to the time it takes to do this, say if someone had it up on a lift? thanks for all your help.