69 340 problems

It has a generic parts store fuel pump on it, and since installation it has 3 or 4 miles on it, and maybe 30 minutes of run time in my driveway. I suspected the pump when I saw only a little fuel coming out of the accel pump squirters, but now I see that the accel pump only puts out fuel from about 1/2 pedal onward. Is this normal? I know it isn't right on a Quadrajet or a Holley, but this is an AVS and I have no knowledge about them. On the same note, the level of fuel in the bowls (with the carb top removed) is about level with the thin metal slosh plated in the carb. Does this sound right? When the top of the carb is held upside down, the floats themselves are level with the top of the carb. In other words, the float and carb top are parallel when held in an inverted position. Does the float level sound about right?

When it sputtered to life last night, it ran as if the timing was very retarded. I advanced the timing with the distributor until it was hard to crank over, and it did start, but only for a second before sputtering and shutting down.

The timing chain is original, and when I had the front cover off, there was only a little play in the chain. How would a guy know if the chain jumped a tooth? It is the original double row roller chain.

I dunno what to do next.
Thanks, guys, for the help.

George