exhaust manifold (downpipe) stud

["Simon Matthews" <simon_atwork@hotmail.com>]

Any idea what size stud is used to hold the exhaust manifold onto the first 
exhaust pipe on an MGA? On removing the manifold, I discovered that one stud 
was missing and the threads had been repaired with a helicoil. I assume the 
stud has dropped out.

Simon