fuel sending unit/gas tank cleaner

[rich67]

best place to get a fuel sending for my 72 gmc? they have one at summit for $40 but it has a vent tube that mine doesnt. im sure it could be capped as my tank is already vented couldnt it? also any ideas on the best way to clean a gas tank. i will have to remove it im sure. looked down in it with a lite after i took sender out and alot of surface rust on walls above fuel level. any kind of bada** cleaner i can get to swash around in there to clean that out? ive heard of people putting rocks in them and tumbling them but that doesnt seem very user friendly. let me have your ideas guys. thanx, rich