Ask Lunati if those substitute springs will work.
The data logger should show it.
In my experience;
When the valves float using a HFT cam, the lifters take up the slack right away. And now the valves will not seat closed.
If while in this state, you allow the revs to come down, she will not idle, cause there is little to no cylinder pressure. It may still run at higher rpms just poorly. When the engine shuts down, it may take hours for the lifters to bleed down. And finally, depending on your PV clearance and lifter preload, it is possible for the valves to get bent.
I have never had a fuel problem cut-off at a particular rpm.
Now, if you hit a rev-limiter or the ECU has an issue; none of the above comes into play. You just back off the revs and everything is normal again, exactly what you described. Grab another gear and away you go.
I think you were right in thinking this was an electrical gremlin.
Perhaps you would want to verify your tach reads correctly.
Some tachs cause reving issues.
Some tachs have built-in rev-limiters
Sometimes an Ecu might crap out like that
Some tachs are incompatible with some ECUs/power-amps.
