Cyl Head exhaust stud spacing dimension?

[reclino]

What is the distance between centers of the exhaust studs in the head on a 1986 911 turbo. I measured 2.575 with calipers. It's hard to measure with the heads on the engine.
Thanks
David

[crg53]

It would be a metric measurement.
Measure outside to outside of the studs with your caliber, then measure the stud and deduct that from your first measurement, you should arrive at 66 mm.