Q: What is the pole-piece spacing for P-90-style pickups? Is it the same as a Gibson-style humbucker or a Fender-style single-coil?
A: The pole spacing for P-90 bridge pickups is 1-15/16″ or occasionally 1-31/32″, which is the same as a standard humbucking pickup. Single-coil pickups generally have a 2-1/16″ pole-piece spacing.
The measurement is taken from the centerline of the low E-string pole piece to the centerline of the high E-string pole piece.