850 double pump issues HELP!!

start with the 30cc [smaller pump diaphram].

It's the shooters that need to go UP IN SIZE [NUMERICALLY HIGHER]

I've done this before, I know what I'm talking about.

42 shooters and maybe the pink cam will help you big time
Also, if you hold the throttle wide open, you should be able to push the lil pump arm down another .015...
If you have 75's in the primary with a 4.5 PV [PV should be rated at Half the manifold vac reading at idle in gear] and if you have NO pv in the secondary you need to go 7 sizes bigger in the secondary.

I would just run a PV if possible in both the primary and secondary and then square up the jetting, as in same size jets primary/secondary.

You should get a holley book and read the sht outta it.