Here's what ya got to do....
back off rockers 3/4 turn, more if you dare(I know, That's a lot of lash, don't over rev engine on the way to the test) That will reduce overlap.
Retard timing at least 15 degrees.. more if possible
there is a round plug on top of the Q-jet that can be drilled out for access to a main metering adjusting screw.. lean that out as much as possible
bring idle up to 1000 rpm min. and lean out idle screws.
I have got a few cars through with that approach. But this is to Canadian standards. gooood luck!