How do you fix a blown headgasket on a Mercruiser 454?

Answer by  DavidS (1517)

First you have to remove the head and take it to be checked for cracks. If there are not cracks then you probably will have to have it machined or the gasket will not seal when you put it back on. One these items are complete you simply clean the gasket surfaces and install the gasket and head. Torque bolts.

Answer by  mannersandsuch (1796)

This is a serious issue that should only be looked at by professional. If you are qualified make sure that you use quality after factory parts and follow manufacturers instructions.