G-body EFI Fuel tank baffles

rwd_pete

Apprentice
Oct 3, 2006
99
18
Niagara Falls
Hi
I'm just working on an LT1/Saginaw 4 speed install in my Malibu.

1a-Malibu.jpg


For the fuel tank I know that you can use a Grand National or TBI Monte but they are scarce. Some time ago I gave my son our '62 Pontiac with a 400 sbc/700r4 (it was originally a Canadian car, 283/PG). The 400 was a gas hog for a student, so we installed a 95 Impala SS motor and trans that was a little easier to live with. I found an S10 gas tank at a swap meet that look similar and moved the plastic baffle and sender over to the Pontiac tank. It worked well.
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I couldn't find any pictures of a G body tank cut apart so I did an autopsy on an old and rusty one that I had.
1- Top View.JPG

2- Sump.JPG


3- gap.JPG


4-gap.JPG


5- height1.jpg


So there are a lot of baffles, but not the labyrinth that EFI tanks have. There is a 1/4" passage at the bottom of the g-body tank that allows fuel to move back and forth. I don't think it could be reduced without cutting the tank apart. Like building a ship in a bottle. I have modified the Malibu tank fuel tank pickup and gas gauge sender to work with the GM style electric in tank fuel pump. Maybe I should have installed an EFI fuel pickup insert like in the Pontiac tank. Has anyone done that? Any pictures? I chose the in tank pump arrangement after having some noisy experiences with inline fuel pumps.

I don't plan to slalom race it. I may try just keeping the tank at least half full all of the time.

Any thoughts?
Pete
 
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Ribbedroof

"That wagon guy"
Supporting Member
Jan 4, 2009
4,157
113
Wellston, OK
Honestly, for any application besides wagon, the new Dorman tank for under $100 on Rockauto seems to me to be the best answer.

Wagons don't have an EFI tank available, but for coupe/sedan or Caminos, why fight the rust and all that welding?

BEAUTIFUL Pontiac, BTW!
 
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rwd_pete

Apprentice
Thread starter
Oct 3, 2006
99
18
Niagara Falls
Honestly, for any application besides wagon, the new Dorman tank for under $100 on Rockauto seems to me to be the best answer.

Wagons don't have an EFI tank available, but for coupe/sedan or Caminos, why fight the rust and all that welding?

BEAUTIFUL Pontiac, BTW!
Thanks for the tip.


After the border opens post pandemic this like like the ticket!

Pete
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
3,335
113
Upstate NY

rwd_pete

Apprentice
Thread starter
Oct 3, 2006
99
18
Niagara Falls

I bought one in January. Then proceeded to cut the crap out of it to add a sump lol.

Why do you feel that you need an EFI tank?
Hi
From what I have read, EFI pickups without efi baffles, will suck air causing engine issues when the fuel tank gets low and you drive in a spirited way. Have you had ok experience without?
Pete

I was just thinking about those auto insurance companies that give you a discounted rate if they give you a motion sensor box to install in your car to prove that you could drive with a bowl of goldfish in the car. Cheaper insurance and no tank baffles.
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
3,335
113
Upstate NY
Hi
From what I have read, EFI pickups without efi baffles, will suck air causing engine issues when the fuel tank gets low and you drive in a spirited way. Have you had ok experience without?
Pete

I was just thinking about those auto insurance companies that give you a discounted rate if they give you a motion sensor box to install in your car to prove that you could drive with a bowl of goldfish in the car. Cheaper insurance and no tank baffles.

If you're NA, then the worst that happens is it will run out of fuel when you stand on it below 1/4 tank and turning. And yes, I have plenty of experience with that. For normal everyday driving a stock tank is fine.

I run sumps and external pumps on all of the G's I've built and I can't really get too crazy turning the wheel sharp and being anywhere near WOT. External pumps are noisier than an internal for sure, so if that's a concern, then buy an internal tank pump. A 450 Walbro will work on a stock FI setup and is able to handle 400whp with it's eyes closed.

Personally, I'm not a tank bottom kinda person. If it'll take 10 gallons then I put it in it. But if you intend to let my wife drive it, then you'll need a baffled tank because she won't put a drop in until it's below an 1/8th lol (I'm hoping you don't know her that well).
 
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rwd_pete

Apprentice
Thread starter
Oct 3, 2006
99
18
Niagara Falls
Thanks for your thoughts Mr. Nailhead. I'll probably take the car to the track someday and it'll likely run 14's. It would probably break the spiders in the 7.5" axle before it ran 13's with a standard trans. My friend took me for a few track day laps in his Z06 and I didn't feel well for a couple of hours. it appears that as long as I don't upgrade the rear axle, that I can get away with the stock tank, surviving by keeping the tank topped up. Nine inch Ford and better fuel tank upgrades next year maybe.
Pete
BTW we bought a 62 Buick Wildcat some time ago. It was somewhat dismantled and we bought it for $400. We took the bucket seats and console for the Pontiac to replace the bench and still look period correct. I still have the power windows. They may be adaptable to the Pontiac. The 401 nailhead was seized and we sold the car to somebody building a similar car. The Wildcat was neat car in it's day.
New Seats& console installed Oct.2006.JPG



You have an LS with a 200r4 behind it? Sounds pretty neat. I bought an LY6/4L80 out of 2007 Suburban. The trans was 4wd so we sold it. I haven't decided what to do with the engine. It would take a lower intake and different oil pan to fit in my Impala SS, but it would jump from ~260 hp to 360 hp. The stock intake might fit under my Malibu hood and would likely fit under my 56 Ford hood. I have a 2004r out of a 305 '86 Regal. Is an LS with a 2004r a happy marriage?
 
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64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
3,335
113
Upstate NY
Thanks for your thoughts Mr. Nailhead. I'll probably take the car to the track someday and it'll likely run 14's. It would probably break the spiders in the 7.5" axle before it ran 13's with a standard trans. My friend took me for a few track day laps in his Z06 and I didn't feel well for a couple of hours. it appears that as long as I don't upgrade the rear axle, that I can get away with the stock tank, surviving by keeping the tank topped up. Nine inch Ford and better fuel tank upgrades next year maybe.
Pete
BTW we bought a 62 Buick Wildcat some time ago. It was somewhat dismantled and we bought it for $400. We took the bucket seats and console for the Pontiac to replace the bench and still look period correct. I still have the power windows. They may be adaptable to the Pontiac. The 401 nailhead was seized and we sold the car to somebody building a similar car. The Wildcat was neat car in it's day.
View attachment 174998


You have an LS with a 200r4 behind it? Sounds pretty neat. I bought an LY6/4L80 out of 2007 Suburban. The trans was 4wd so we sold it. I haven't decided what to do with the engine. It would take a lower intake and different oil pan to fit in my Impala SS, but it would jump from ~260 hp to 360 hp. The stock intake might fit under my Malibu hood and would likely fit under my 56 Ford hood. I have a 2004r out of a 305 '86 Regal. Is an LS with a 2004r a happy marriage?
My son has a 200-4R behind a Motown LS (World Products block that uses SBC bottom end and LS heads). The 200 works very well, but needs clutches every 15-20K. Not a big deal really, but it is a maintenance item only because the motor makes a lot of power.

Your LY6 program would be a good one. Yu can swap a 2wd tailshaft onto the 4wd 4L80 for about $150 in parts, but the trans has to be completely torn down to do it.

The Nailhead you had would've been a costly motor to rebuild/repair. I was fortunate that I only needed a basic overhaul kit and a valve job.
 
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rwd_pete

Apprentice
Thread starter
Oct 3, 2006
99
18
Niagara Falls
Thanks for the info on the 2004r. I had heard about those blocks. Neat stuff. I haven't had good luck with my trans work so I sold the 4L80. I paid $600 for the package and sold the convertor to a Turbo LS truck guy that had fried his convertor for $175. Then an 11 second Turbo Blazer guy bought the trans for the case for $200. Both had GM tags as factory replacements.
I put a low mileage 700r4 in my 56 Ford 400 sbc and when it made it's first shift into second it went into "neutral". I had too many projects on the go last summer and parked it. Hope to figure it out this summer. I thought I had the TV adjusted right.
2014-10-12 at Toronto Motorsports part.JPG
 
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