[coffeeman]

I have a 1999 GEMS P38 with a blown head gasket. One of the threads in the block is stripped. I need to insert a helicoil but am not sure of the size to use. I know the pitch is 14, but is it metric or american?

 

[Rich998a]

Most of the main engine measurements are imperial.

 

[coffeeman]

Thank you I am probably looking at a 7/16 14 helicoil.

 

[Rich998a]

Can't help you directly as I'm away from the workshop. However, all the main block/head and all the other bits are the same as they were on the 3.5 and the Buick before that. May be worth cross referencing that engine as well for an answer.