Hole diameter for 69 b body tach wire grommet?

[railer69]

Installing a Tach on my bird and need to know the stock hole size that has to be drilled through the firewall dimple for the grommet. Thanks!!

 

[monroegtx]

Hi railer, I assume it would be the same as a '70 GTX which has a 7/8" hole drilled at the dimple.

 

[railer69]

You're the man! Thanks for the input....

 

[red 69 runner]

When I did mine I used a step up drill bit and just kept checking until it fit perfect

 

[railer69]

When I did mine I used a step up drill bit and just kept checking until it fit perfect

That's a great idea! Thanks