360 does not seem to be making power and is slow in the 1/8. Need help and/or suggestions

Hes got a decent combo of parts wrapped around a engine that should make 425hp or more. It looks like its making 250hp, maybe. Find out why.
Fuel pessure and volume check? Compression check? CAM timing check, not just ignition timing? He has at least a hundred horsepower missing, and the engine is struggling and wont rev. I find it hard to believe that is a drivetrain problem!