not getting any fuel

340 died on me the other day. Got it started for a little while but would die on idle. Lots of rust in the filter.

Blew out the lines, installed new mechanical pump, new filter, replaced rubber lines front/rear, crank it and get nothing out of the hose. Tank and sender were replaced less than 10yrs ago by previous owner. Can sending units just go bad? If it is the sending unit, how hard are they to replace and do I have to drop the tank or can they be pulled with the tank in the car (67 barracuda).

thx in advance