Not enough compression?
Im seeing the heads change, pick up a little power but still need to fix something else.
Exhaust?
Also, is the tune spot on? how many degrees of timing are you running and what dyno?
At 18-19 psi you are at 32.7-33.7 psi absolute which means you will need a minimum of a 2.5 bar map sensor, but why not go with a 3 bar at that point and a 3 bar operating system and have some head room. Sounds like some crap to me, but then again I tend to plan a little over what I need...sorry rambling a bit, but sounds like you might be dealing with some BS.
The Best V8 Stories One Small Block at Time



