Buick GNx sending unit and pump

theIrishman

theIrishman

Not-quite-so-new-guy
May 27, 2018
11
14
3
#1
Has anyone had success with using a Buick Grand National fuel tank sending unit and pump (or aftermarket high volume/pressure pump) in a 1978 and up Malibu fuel tank, Ls 5.3?

Or has anyone modified an original Malibu sending unit to work with an in-tank electric pump, and added a return line?
 
Last edited:
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Pronto-

Not-quite-so-new-guy
Dec 4, 2014
33
26
18
#2
If your going FI then you want the tank for a Turbo Buick with the dog dish and splash guard so you don't end up sucking air on a hard corner or launch.
 
UNGN

UNGN

Comic Book Super Hero
Sep 6, 2016
2,595
1,051
113
Southlake, TX
#3
A GN tank has a sheet metal wall that runs down the middle:

t-type-tank-2-jpg.90150


Doesn't do much for corners, but makes sure the pump doesn't suck air when accelerating. Carbs have bowls and don't have to worry about a couple seconds of air..
 

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MC96

MC96

Master Mechanic
Dec 7, 2015
254
111
43
#4
Ive been told the FI sender in a non efi tank isnt a big deal in autocross, as long as you have it above 1/4 tank.

I would imagine you wouldnt see many issues street driving it
 
UNGN

UNGN

Comic Book Super Hero
Sep 6, 2016
2,595
1,051
113
Southlake, TX
#6
In autocross, I wouldn't trust an EFI tank with less than 1/2 a tank. My T-type will starve on an aggressive on ramp at 1/4 tank. Yes, I probably take onramps faster than most people, but factory GN tanks are really only for acceleration and not for cornering.
 
20Grand

20Grand

Apprentice
Mar 16, 2018
59
10
8
#7
I’m using a fuel tank from a Monte, about the same as your GI, and just drove it across the country. I’m using an AC Delco pump tho.
 
20Grand

20Grand

Apprentice
Mar 16, 2018
59
10
8
#8
But, I think you can get away with the stock tank with upgraded pump and sending unit. My mechanic that builds LS swaps also confirmed, but wanted to be safe on long distance trips. If you do the swap, order without fuel tank neck and order YOUR fuel neck and install.
 
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