Plugs

I have a preference for the 1-49/64 plugs too. I've gotten into the habit of cleaning the block surface with a bit of sandpaper and installing the plugs in iron blocks with a very light smear of JB Weld as a sealant/adhesive. On aluminum blocks I will use the Motorcraft gray silicone for diesel applications instead of the JB Weld - it seems more flexible but still holds up well.

On oil galley plugs that seem kinda loose I will lightly stake them at 2 or 3 spots by using a punch to disturb the metal around the hole after the plug is in place. I much prefer to thread them - but some of the blocks are drilled so far off toward the edge of the casting where I am afraid that the tapping operation would crack the block. The 1/4" NPT pipe tap says to use a 7/16 drill for the starting hole, I will often finish the top quarter inch or so with a 1/2" drill so that I don't need to put so much pressure on the tap going into cast iron.

Barry Rabotnick
Survivalmotorsports.com