engine to frame bolt hole size

I need to get a helicoil kit to repair on hole that is no longer gripping the bolt. This is one of the 12 holes toward the fire wall side where the 355 engine subframe mounts to the frame. I remember it to be 12mm, but not sure if it is 1.25 or 1.5 (I am not home so I can't measure it), and what length the helicoil has to be.

Does anyone have these numbers ready at your fingertips?

 

Thanks.