340 power ??

The power should continue to rise until the valvetrain gets unhappy....... which will very likely happen before the rest of the combo gets “used up”.

If it were a similarly sized solid cam it would easily peak over 6000.
Hydraulic lifters?
You’re at the mercy of the lifters.

You’ll notice on the HR test with the magnum heads it died at 5800.
It didn’t “fall off”...... it nosed over...... hard.