16 gallon to 20 gallon anyone done this?

[frotosride]

I did the opposite of this with my 81, came with one 20gallon tank and I had a spare 16 gallon that I had taken off another truck.
I had to change the filler neck etc but when I went to bolt it up only one side of the supports lined up to the holes in the frame!

sent from my pofs galaxy 4

I'm finally it seemed as though I had the same problem but it was only by fractions of an inch so I loosened the straps onbothe ends with the forward on having all bolts in then I just tapped the mounts into position. When I get back to Main next week (in GA now) I'm going to install it with the straps already loose.

[LTZ C20]

Ok I'm not sure I understand how the baffles are shaped. Maybe it would make more sense if I saw it as a whole, like the whole tank cut in half long horizontally front to back. Cuz that just looks like a tray sitting on the bottom of tank. Keep in mind I've never seen or handled a tank like that in person, I've only worked with my fuel tank and the newer plastic ones from the late 90's and newer.

It is literally a rectangular bowl with holes in the bottom for when the level is lower then the upper lip of the bowl and to prevent fast draining.

OOHHH, light bulb! I got it now. So those square shaped bosses in the middle with holes in the middle, are those bosses raised above the floor of the bowl or depressed lower than the floor of the bowl? So that bowl is the baffle in its entirety, there are no other baffles in the tank, just the bowl?

[frotosride]

If you look at the first picture you will see a slight low point in the shape or a square. The baffwl/bowl is slightly recessed imnto this and the holes in the bottom allow slow drainage of the bowel.. Thus the baffling... Simple b t effective. It's a lot simpler than that OE. 2hen I get back I will post the nest pic oi can of the factory baffling.

[LTZ C20]

Ok sounds good. I didn't know the factory tanks and the aftermarket ones were baffled differently. So you think the aftermarket ones are better? Think it prevents fuel slosh/gauge needle bounce better?

[frotosride]

I!M wondering that myself... The bowel that makes up the baffwl is higher so maybe at lower fuel levels but above the baffling I doubt it. The factory baffling likes like a maze for fuel. Kinda neat I thought and effective down to the last gallon. I always thought I had dual 15 gallon tanks because I would run them dry for a while and then switch tanks. Never could get more than 15 gals in one

[Captkaos]

Factory tanks used plastic baffling.  it is generally a square box surrounding the pump on the 87-91 trucks.

[LTZ C20]

I!M wondering that myself... The bowel that makes up the baffwl is higher so maybe at lower fuel levels but above the baffling I doubt it. The factory baffling likes like a maze for fuel. Kinda neat I thought and effective down to the last gallon. I always thought I had dual 15 gallon tanks because I would run them dry for a while and then switch tanks. Never could get more than 15 gals in one

Haha, probably cuz you still had 5 gallons in them everytime you switched tanks or filled up.

[frotosride]

Ok so here's the lines. I converted the hard line to -6 bc this is the sending unit for the 6.0l swap and I already converted it. So far in have over 250 miles on the tank and everything is doing good... the bouncy needle isn't ever going to change. I could probable soldier a delay that may prevent it or at least minimize how drastic it is... we will see.

[philo_beddoe]

Not to change the gas tank topic, but you mentioned bouncing fuel guage needle. Mine has bounced for years, not the tank at all.  The needle itself on the guage simply wears out, the resistance is lost.  With the guage out, if you shake it the needle should not move.  I just pulled this original out of a cluster.  When shaken..no movement!! Finally!!

[philo_beddoe]

Is this tank for the same blue truck i saw when i picked up the tire carrier?  Oh here it is by the way, all sanded primered and painted GM gray.

Ok, back to the gas tank topic.

[frotosride]

Yup that's the one. 8 may tey and swap the gage. But not now.
Oh the tire carrier looks great

[frotosride]

LTZ, it took me a while to get around to it but here is the baffels from my OE 15 gallon tank. For almost 30 years it looks good. I cut it up bc it's gonna be for the run stand for now until the 'Man-Kart' project needs a baffled tank. I will be welding it up on that side for the information of all those who noticed how useless it is missing about 5 gallons of tank.

[LTZ C20]

Factory tanks used plastic baffling.  it is generally a square box surrounding the pump on the 87-91 trucks.

So Froto, this quote by Capt is actually exactly what your picture shows that you just posted. A square plastic box surrounding the pump. If I purchased a new, replacement tank, it should have the same, or try to find good OE tanks, maybe even NOS tanks. And that should solve just about most if not all of the fuel slosh needle bounce.

[frotosride]

No, unfortunately... I have the new baffled tank and sending unit on my driver's side and just a new sending unit on the passenger side but the bouncing continues. I blame it on the For# parked across the street.

[LTZ C20]

Well fudgesicles...