Join Date: Mar 2009
Location: Huntsville, Bama
Bronco Info: '78 Bronco XLT - Buck the Truck
I recently put in a poly 33 gallon tank JBG 33 gal sending unit and my gauge still reads E (I think the wiring to the unit needs attention). If the gauge was just a little off, I wouldn't worry about it, but the main thing with using a 25 gal sending unit with a 33 gal tank would be that you never get use of that extra 10 gal you have to carry around to make the truck go because the pick up tube would be a few inches of the bottom of the tank.
Pics and notes of my recent install are in my build thread. I thought about making an access hole while the tank was out, but decided to just go the normal route of draining and dropping the tank. The worst part about dropping the tank IMO was breaking all the old rusty bolts loose for the lower tank straps and then removing them because PO installed a tow bar that hindered easy access to the nuts on the underside. As far as putting the new stuff back together, the worst part was the filler hose to neck connection, but that was due to specific parts that weren't exactly stock. One reason I chose to not do the access panel is because I may go to EFI and in tank pump in the near future and I figured it would be more of a pain to install/test all that setup using the access panel than outside of the truck.
If the PO recently installed the tank, those bolts should spin right off easy. If I did go the access panel route, I think I'd do seam sealer and a rivet at each corner.