dont know what to tell you, boss, I think you should just buy one and maybe you will be surprised because it sits in such a way that will make you think "Oh ok"

But im not sure if that guy is quoting himself or what there

 

Cancel what I said before, this guy here seem to indicate that the owners manual has a footnote on the 4x4, LWB(8 foot) with E4OD, and that is you have a 16.5 front (side) inside the frame rail gas tank. Perhaps it has to do with the output of the E4OD or the placement of the transfer case(What Tcase you got?)

 

The Fuel capacity for the front tank ..... footnote in the 1990 manual is (3) on a Regular cab F150 LWB 4X4 . It shows that 3 is E4OD transmission and is for all EFI motors.
Pages 378 and 381 for this info.
https://www.fordservicecontent.com/F.../96f23og1e.pdf

 

must have stayed the same into 91, makes sense. Wonder what the clearance issue was lol

 

Gotta be because of 4X4 with E4OD.

 

I mean, didnt later years have a bigger tank? maybe just choice of t case or somethin

 

He said the transfer case was to close so if that was the problem and the E4OD combo caused it, I Imagine you are right.

 

Thanks for all the replies I'm relieved I went ahead with the 16.5 tank haha and to know Im not the only one. It must be because of how large the E4OD is, for those wondering I have the Borg-Warner 1345 T-case. From what I understand thats a pretty good one and from my past experiences even with open diffs my truck is way more capable than most would think it should be! I got the replacement Dorman tank (price matched RockAuto at Autozone and saved $40!) and the fuel pump should be in today and tomorrow I'll put it all in. I'll be coating it in RP-342 like everything else. Just installed the new rear tank and pump with new straps that I glued rubber inner tubes to to help with any rubbing. Looks better than new now and coated all the inner frame too!

 

Yeah it's the E4OD causing it, that thing is hella long. If you insisted on having a large capacity front tank there is the 95-97 plastic thing that some diesels had, it's got like 20 gallons capacity (at least that's what mine took to fill from empty) and it can accept the high-pressure gas-job pump but good luck finding one of those and even if you do b you still gotta extend pump pickups and such. This is one of those moments where replacing like for like just makes most sense, any potential benefit of the larger tank will be more than offset by the aggravation you'll have with the clearance issues.

Good job on the rear tank btw 👍

 

Amen to that couldn't have said it better myself thats why I just settled on keeping like for like haha and thanks for the compliment!

 

Well guys thanks for the help, got it all installed and works great! Only odd part was trying to reroute the lines since the new pump has different shaped fuel spouts.