s13 turbine outlet bolt size

[psidriven]

Couldn't find this info using search. Here's what happened, guess the bolts and studs holding the o2 housing to the turbine were not torgued properly and rattled loose. Now all I have left is one bolt holding the o2 housing on. Need to find replacement studs and bolts before the whole thing falls off. Saw that ATPTurbo sells studs and nuts but need to confirm the size. Don't have a thread gauge and don't really trust them with exhaust parts due to the corrosion, scaling.

thanks in advance.