Engine symptoms - diagnosis?

[desertPOS]

I have a '69 C20; 350/quadrajet, TH400, ho52 RA. Anyway, the truck runs great overall, but during initial startup when it's cold I have to give it extra gas to keep it going for about 10 seconds or so. If I don't give it any extra gas it will start up and run for about 2 seconds then it dies (I always pump the pedal three times before I start it cold). Other than that it runs very well. However, it does diesel a little intermittently when I shut it off, and during all operating temperatures seems to stumble if I put the pedal down all the way (like cuts out for a half second, THEN accelerates). Anybody who can tell me why or how I can fix this would be much appreciated!

FYI, Things I've done recently to the engine are new fuel filter and HEI ignition. First things that come to my mind are possibly haven't gotten the timing set perfectly, never tried to 'dial in' advance curve on new distributor (cheapo from sumit). There is also some fuel leaking from the front of my Qjet that I haven't traced out yet. Thanks for the help! I just want it to run a little better...