Stock 340 dyno tests?

340 was rated at 5000 rpm. It might have made 285-290 at 5300-5400. Every one I've ever seen in stock form didn't do squat for power increase over that 5300 number.

Hate to say it but an XE268H with stock heads/rockers with an RPM intake/carb is a 1.0ish hp/ci formula.

Putting a good valve job on these things makes a big difference. The factory stuff... MEH. Might be why these "stock" rebuilt engines tend to run better with machining tolerances and better products going into the build. The days of drive it 500 miles to knock all the crappy machine work into shape... gone.