Stripped Holes in Cylinder Head for Intake Manifold Bolts

Hey All,

I was putting my intake manifold back on to my Small Block 360 when two of the bolts just spun upon becoming flush with the surface. After looking closely I realized the threads were definitely shot.

They are cast iron heads and I figured I could carefully attempt to heli coil them, but I realized the holes are on a slight angle from the surface of the heads. Does anyone have info on the angle of these holes? I thought I could measure the angles with a gauge of some sort and then use an aluminum block with the same angle drilled holes to steady the drill for the pre heli coil drilling.


Anyone have thoughts on heli coiling into a cast iron cylinder head at an angle? Any tricks or am I going about this the wrong way.

Thanks