Pontiac 1 61/64 Brass Plug For Side of Block, Each

The coolant core plug for a Pontiac V8 block, in brass instead of steel. Steel plugs rust from the inside out and are the usual reason a freshly rebuilt engine is back out of the car two years later; brass does not corrode the same way and costs a few dollars more for the whole engine.

A 1967-and-later block takes eight of these — three per side plus two in the rear face. A 1966-and-earlier block takes six, two per side plus the two in the rear. The two rear plugs sit behind the bellhousing flange, so they get replaced on the engine stand or not at all.

Clean the bore back to clean iron, sealer on the outside diameter, and drive the plug in square with a driver that contacts the outer rim — hitting the center of a cup plug distorts it and it will never seal.