Does anyone know the size of the nuts needed for the studs that mate the exhaust Y pipe to manifolds? There are 2 studs per manifold where the stock exhaust bolts on with the flanges. Thanks!

 

14mm or a 9/16" will work, depends on how corroded they are....

 

I should have been more specific. I need to get new nuts.
I lost em somewhere along the line in the 5 year restoration. I am thinking they are standard size, but didn't want to take a header off and carry it with me to the hardware store.

 

i believe they are 10mm fine thread !!!!! u u can still get them at chevrolet !!!!!

 

It's a 3/8" standard course thread 20 or 16??? I think 20....

 

Great, thanks!