I used a VW fuel filter in the end of my vent line for my tank and tucked it up inside the frame rail . As for your gas line take the original line and straighten it out where it turns to go to the stock tank and route it to the rear , where it ends put in a fuel filter then continue back to the new tank with 3/8 steel line, use brake line tubing. I think the stock fuel line is 3/8 already. Thats the way I did mine and never had any problems.
The rearend in my pickup is from a 64 to 67 Chevelle 10 bolt and is 60 inches wide , fits great with 8 1/2 inch American mags.