Well it's been so far, so good. I thought about a sump, but decided against it.
When I did the 6.9 install in my '86 Bronco, I just used the Bronco tank that was already in it. The feed line for the 6.9 hooked right up to the feed line on the Bronco sender. I ran the return into the filler neck. If anyone doesn't want to do that, you'd have to figure out something for the return. I had a guy tell me that in 1985, the trucks were all EFI. In 86, the Broncos that cam out with a 351W had a carb, but the ones that came out with a 302 were EFI. In 87, all of the Broncos were EFI. I've never checked into this for myself. Just to be safe, I ordered a 1985 Bronco tank. I thought about ordering a 1985 Bronco sender, but since this is only going to be used for a transfer tank, the gauge will never read from this tank. I'm just going to use a piece of fuel line and attach it to the pick up on the sender.
One final though regarding the 85/86 EFI vs carb thing. It's possible that only the small block trucks had EFI in 1985. The 460 trucks may have still had a carb. It almost seems like I've seen/heard that the 460s had carbs in 1987, but I can't remember that part. I do know that the 460s had EFI in 1988. Of course this thread really isn't about gas engines anyway.