what size are the smallblock exhaust studs? Can i replace 1 with a header bolt?

[getslideways]

Does anyone know what the sizing is on the 2 end exhaust studs for each head?  I know the thread going into the head is 5/16 what is the thread pattern on the other side. Anyone know the length for both ends?

Is it not a good idea to just use a header bolt in place of one of the studs?

I have one stud thats messed up, and i am installing a set of headers so i am trying to figure out the best way to remedy this situation is?  If its fine to just use a header bolt with thread sealer (because of the water jacket) i'll just do that.  I just thought i had read that it wasnt a good idea, though i cannot remember why.

[Chryco Psycho]

it is a 5/16 coarse thread on the stud into the head , you can use a header bolt with sealer but if you have to drop the header for any reason you will now have to drain the coolant

[getslideways]

thanks! yeah i ended up going with a header bolt and using thread sealer on it so far so good!