Does anyone know where i can source some the studs that go in to the head, on the inlet manifold side. I do have an old head with new studs, but I can't seem to remove them with mole grips.

 

Use two nuts, one tightened against the other to remove the studs.
If not, they're nothing special, any fixing/fastener place will have them

 

To clarify the 2 nut method:

Run the two nuts onto the thread until the stud is sticking out of the second nut; tighten the two nuts against each other (two spanners in opposite directions) until they are locked, then, using the first nut, you should be able to unscrew the stud. Can take some force (tightening against one another) to crack the stud loose

 

I will give it a bash tomorrow, thanks