To add to the mix ... I have a .47 and it has all the mods from this thread and with the idle needle set to .003 ...IT seems to run fine but the low end is still a bit boggy for transition ...top end rpm seems a bit slow ( with out a tac I am not sure ) .....BUT.... when I use a one way pressure valve I have been able to tweak out the top end for a bunch more RPM and I sure can hear it from the sound.

I had to tweak low end but not much.

So in this case pressure did make a difference.

just my $0.02