High rpm miss

Have you taped a fuel pressure gauge to the windshield and made sure it stays at proper fuel pressure?

Springs crossed my mind; so none broken?

Acting like a rev limiter seems more like fuel or electrical, though, and I would first look at electrical with it missing at the same RPM in each gear.

• Plug wires: Check for end-to-end resistance on each one, plus the coil spark wire
• Coil could have gone bad; easiest to diagnose by R&R. What coil model?
• Moisture and dirt under the distributor cap was common on 302's/289's, with the distributor up front and the fan blowing carp right on it.