What size tap for spark plug CA77

[texasgrape]

PO cross threaded one of the plugs. I need to chase the threads. What size tap do I need? Plugs are D8HA, 1967 CA77. Also what about the small amount of fine shavings going down the cylinder? Is that a concern? Vacuum them out?? Thanks.

[texasgrape]

After talking w/NAPA and local mechanic, it's a 12mm x 1.25. I bought one at NAPA and it says: Spark Plug Tap on the package.

[texasgrape]

Lastly, just a tip to keep shavings (if any) out of cylinder: I used assembly lube in the big grooves of the tap; it's sticky enough that the shavings stick to it. If you don't have assembly lube, a thin coating of grease. Use oil as you tap and don't go for it all at once. A few threads then back it on out and clean tap, repeat . . . worked for me.

[james robert]

Texasgrape, Somewhere around here I have a tread chaser that i bought from an auto parts supplier. It came with two different thread sizes.I would get one of those and see if it fits the undamaged plug hole first. I think most plugs are a standard thread size.

Ops I just seen your above post.