z28oc91

iTrader: (1)

hey guys this is a stupid question but i cant figure it out, im wondering what the nut/bolt size is unerneath the car (00 z28) that would connect the stock headers/cat to the y pipe..im trying to get my hookers in but the bolts are so rusted i can not tell. i think its either 1/2 inch or 14mm?

Darkman

iTrader: (2)

9/16 is interchangeable (most of the time) with 14mm.

1/2 inch equates to 12.7mm which means sometimes a 12mm will work and sometimes a 13mm will work. (Depending the tolerances of the tools/fasteners.)

z28oc91

iTrader: (1)

idk it seemed like when i was using the 9/16s it was too big, it seemd 1/2 or 14mm stuck better, the reason i ask is i just dont wanna strip this **** out of it on top of it being all rusted

Darkman

iTrader: (2)

Don't forget to try a 13mm which GM uses with some frequency. I use metric tools almost exclusively on late model GMs. Occasionally, you will find a fastener that has been replaced with a standard size.

z28oc91

iTrader: (1)

okay thanks for the advice!