Going to switch out the sending unit..

diymirage said
On my 71 duster
It started out as a /6 and is now a 408
I plan on upgrading to a 3/8 fuel line and using the stock line as a return

Anything I should look out for, or is this a simple project I can do with the car on Jack stands?

Maybe maybe not. there is little room for a 3/8 feed and 5/16th return sharing the same space.