Sorry, but you really have not answered any questions here.
79 USA 1 and I have both asked if you have a code reader plugged in. And I'm still unsure as to if this is happening when the car is running.
If you do in fact have a code reader plugged in (or paperclip,) and this code ONLY comes on with the key on, and NOT when running, then this is nothing to worry about.
If it IS flashing this code when running, your ECM is not getting ignition signal, which could likely cause runability problems.
And if YOU DO NOT have a code reader or paperclip plugged in to the ALDL, then I have no idea what could cause that aside from a very coincidental short circuit.
My honest opinion is that your new carburetor is junk, or you have too much fuel pressure. 8-10 is a little high for a carb, even a little high for a mechanical pump to be putting out.