Ported 317 Flow Numbers
This means the flow is turbulent and inefficient at that lift and port speed (which is probably too high).
If it backs up on a bench with only 28" of water it will probably backup at .400" lift when the engine is seeing 100+" of water during its actual operation.
I say make them fix the port speed (even if you lose a little flow) and you will find good power.
Good luck.



