Holley help/ twin 750s/5psi boost/roots
 

twin holley 750 blower carbs on a weiand 256 set at 5lbs boost
carbs are blower carbs with boost refernced power valves on the primaries
primary jetting is 74s secondary jetting is 85s
AEM wide band O2 reader/data logger
509" approx 9-1 cr stock HP500 heads with inconels and 1.8 rockers,
custom cam, more lift less duration than stock HP500 cam
runs 11.7 on prmaries = too rich
runs 12.5 on secondaries/WOT = too lean
has a dead spot at around 2000rpm were it goes scary lean
will die if you come off throttle too fast..

carbs are off now and I am cleaning and rebuilding,
power valves seem ok but I will be replacing them regardless,
wondering what PVs I should be using and which way to go on jetting and anything else you can help with..

call Patrick from Pro-System