Have you pulled the existing spring to confirm that it is the black one?


""Primary jets are 74 (original jets were 70) and it has a metering plate for the secondaries that works out to a 75 jet.""
A 75 secondary jet seems lean on a built 440 to me.


What color pump cam and what size squirter do you have in it?


Are you are getting 12"hg in N or D?

I think that one of your circuits is lean. Either the pump cam is too small, the PV is too low, or the secondary plate is too lean.