depends on the block. Older stock blocks have a 2 piece seal. It can be changed by dropping the pan, and the rear main cap. The only specialty tool needed is a small screwdriver.
Newer stock and all aftermarket blocks have a one piece seal. You have to pull the trans and clutch to change it. You also need a special seal driver. You do not need to drop the
oil pan or remove the rear main cap.
Both seals, when installed correctly, will last just about forever. Every
oil leak from anywhere on a SBF shows up on the front of the block plate. It looks for all the world like a RMS leak, when it could be from a valve cover, or a fuel pump cover.