you should be able to run 11's w/ a 10psi fuel pump. I have had freinds run 6 pack cars to 11.70-11.80 w/ 5/16 line and Carter street strip pumps. You have major tuning issues. You also have low compression. Those speed pros AT BEST are 9:1 I'd bet you are probably closer to 8.5:1 especailly if you are running Fel-Pro head gaskets. You should probably get a good timing light with a advance and curve you distrib. Have full advance come in at 2200rpm and start at 36* total. I'd bet w/ that compression 38* would probably work better.
I love the looks of a 6-pack and they can run like heck but they are tricky to tune (for regular 4bbl guys like me) If it dies from a dead stomp to rhomp I'm guessing it's going dead lean. Good luck.
P.S. Dump the vacuum advance.