My son and I have been busy trying to get our 1987 F150 running with both tanks. We ended up with a junk yard sending unit/pump in the rear tank and a new NAPA sending unit/pump in the front tank. We had cut the fuel lines earlier and have had to use rubber hose to replace them. We are planning on replacing them sometime in the future.
After getting everything put back together the truck would run fine on the rear tank but not so good on the front tank. It would stall and die at low rpm's on the front tank. If you kept the rpm's above about 2K it would stay running. When it did die you had to switch it back to the rear tank to get it started.
In trouble shooting we switched the supply & return lines between the two tanks at the selector valve thinking the selector valve was going bad. After the switch the problem stayed with the front tank.
Then we switched the supply & return lines at the front tank sending unit/pump. After that everything is runs great.
I didn't think it would run at all if the supply & return lines were swapped but it does. Somehow in getting it back together we got the supply & return crossed at the sending unit of the front tank. Once we got them straightened out everything runs fine.
My son and I are working on this truck together and learning as we go. We definitely learned a lot yesterday.

 

I wish my dad was around to help me. I had to learn by the old technique of taking bolts out until the part fell off. And I always had leftover bolts....

 

yeah they are the factory extras, thats what ive always called em lol

 

Yeah, no dad here. I learned the basics from my mother, but once I started taking apart things to get to other things to take apart, I was pretty much on my own.

Yep, only need about half of them, half of the time. That's... what... 25% of the bolts in a truck are unnecessary, and can be removed to lighten it up and get better MPG's!