I've got a set of 291 2.02 1.60 heads with matching cast dates. I believe they are F27. is there any way to tell if they were originally 2.02 1.60?
Note the machined relief in the chamber wall adjacent to the outside of the intake valve in the photo below of a 186 head with factory 2.02's; the 291 will look the same way if it had 2.02's from the factory. If it has 2.02 valves and the unshrouding cut isn't present, they were 1.94's from the factory and the shop that installed the 2.02's didn't make the unshrouding cut.