Exhaust stud

[Vince]

One downside of using big bore headers on triples is it makes getting a spanner or socket much harder to get on the stud nuts and doing it on a hot exhaust is pretty deadly.

 

[martymoose]

11mm or 7/16"

 

[Paul Marx]

My (was) small valve SF - head bought to allow significant rework of port shape - had 7mm ex studs. Didn't know they'd changed to 8mm. Figured i may as well up them to 8mm to match my big valve head and ex flanges and add a little strength.

They went to 8mm on the big valve heads because enthusiastic tightening broke studs obviously.
Paul