[michaeld]

Hi guys,

So I've got a 73 Grandville with a 7.5L and I need a new gas tank and fuel sending unit.

I've actually got an old 1973 "Part Number Service Guide" which according to the guide applies to all models "except Grand Prix." It's dated December 1, 1972.

All that to tell you that according to this guide, the OE part number for my 73 Grandville fuel tank would be 411934. And the OE part number for the fuel sending unit w/ A.C. would be 6429289.

The only distinction made is for a station wagon vs. everything else and w/A.C. vs. w/o A.C.

So I thought I had this figured out.

But when I try to get the tank and sending unit, I'm told that these numbers ONLY correspond to the convertible. And yes, I DO wish I had a convertible, but I've got a 4-dr vinyl hardtop and I need my dang parts.

Could someone clarify whether the convertible had different parts from the hardtop vinyl and if so, what the correct part number would be for my car please? I have a feeling the parts place is wrong and my part guide is right, but I'd sure like to verify. Thank you.

[David Brown]

I don't know about your 73, but I can tell you that new tanks for my 70 Bonneville convertible are not available. Many guys inquire about tanks for big cars our this era and they aren't available. If you own a A body GTO or lemans, everything is available and reproduced. There may be some parts from other models or years that could be used. I also have a 74 Grand Am. They don't make a sending unit for it, but they substitute one from a 74 Lemans. Only problem is the Lemans is a 21.8 gallon tank and the Grand Am is a 25 gallon tank, so the lemans unit probably shows empty when 4 or 5 gallons are still there, and the pickup tube isn't long enough to reach the bottom of the tank, so those extra gallons are not able to be used. My solution was to send my sending unit to be rebuilt, and it now is better than brand new and works perfectly. Tanks can also be repaired if needed. Some suggest a good radiator shop that can clean and solder any leaks. I sent my sending unit to Bob's Speedometer Service www.bobsspeedometer.com who does speedometers, instruments sending units etc. 800-592-9673

[michaeld]

Hi David, thanks for telling me what you know.

Here's a picture of my Part Number Service Guide, Pontiac 1973 dated December 1, 1972. In parentheses it says, "Except Grand Prix." At the bottom it says, Mitchell Manuals, Inc.

At least, I tried to load the picture. Anyway, if that part number service guide is valid - and I truly don't know why it wouldn't be - then the part numbers in the guide are correct and the part stores are incorrect. With the only exception being for the Grand Prix. I actually see the guide refer to the convertible and to the station wagon, and to the Grand Ville. My view is that the specific vehicle is mentioned when and only when the part is different. Otherwise it would be the same part. Am I wrong?

The question is: does the 73 Grandville hardtop have a different gas tank and a different fuel sending unit than the 73 Grandville convertible?

[jamesq]

Rockauto lists the following tank for a 73 Grandville:

https://www.rockauto.com/en/moreinfo...zGDIoOhQ%3D%3D

They show your original part number as a cross reference!

I hope this helps!

James Q

[michaeld]

Hi Jamesq

That's the thing: the LILAND GLOBAL IGM40J which corresponds to Pontiac Part number 411934 is the same exact unit I am looking at at Carparts.com. It's cheaper at CarParts.com because RockAuto charges like $142 shipping and it's like $25 at CarParts.com.

Same exact unit at both places. But CarParts says this tank ONLY fits the 73 Grandville convertible and NOT my 4 door hardtop. Same with the fuel sending unit, Pontiac part 6429289.

Does the convertible have a different gas tank than the hard top Grand Ville?

I am not able to get under the car and look as it is at a mechanics and the car is not positioned to be jacked up and I am supposed to provide the parts before they work. So I'm not able to verify by looks or bolt pattern. If the convertible tank is the same-same as the hardtop, then I'm good with the Liland. Otherwise, CarParts.com is correct and that tank ONLY corresponds to the convertible. I'd really like to make sure.

Btw, my Part Number Service Guide lists a different fuel tank for the 73 station wagon: part number 412259. Those are the ONLY two fuel tanks in the service guide.

So does the 73 Grandville convertible have the same gas tank (Pontiac part number 411934) as the 4-dr hardtop sedan Grandville?

[Held for Ransom]

My '74 Parts Book lists a '74 B-body gas tank for all and another for HDC and SW. Fuel sender is the same (2 PN's). '73 sender is the same for '74 and that number is the one you have listed.

[Stuart]

I checked the online parts database here on the site. I wasn't able to find anything for p/n 411934 (the database isn't necessarily 100% complete) and for p/n 6429289 it said all B body cars 1973-1975 except station wagons and heavy duty chassis. A station wagon tank is different because it's inside the quarter panel and not under the floor, I'm not sure what the difference would be for a heavy duty chassis (i.e. police car or taxi cab.)

[camerjeff]

The difference may be if the fuel tank is baffled or not? I know my 1971 Catalina Fuel tank is Baffled and it requires a Canister type fuel sending unit. Both are not available. I ended up having my original tank cleaned and resealed an lined, and having the fuel sender rebuilt.

If the LILAND GLOBAL IGM40J tank fits the car I would go with it. What is the return policy for CarParts.com vs Rockauto? If they will accept a return if it won't work I would try it.

As for the difference between HD Service tanks and (taxi & Police) it is usually the vapor return system due to the large amount of time those cars idle compared to "normal use" cars. My 71 Catalina is a Police car, and it actually has 7 different vapor return ports built into the tank? Why they didn't just connect them all to a single larger inlet I do not know.

Good luck with the parts hunt!

[David Brown]

Generally speaking, convertibles have heavier duty frames because they do not have the roof to help stabilize the car. That might be why the regular tank won't fit.

[michaeld]

So Held for Ransom is saying there IS a different part no for the convertible (that's the HDC)? I first thought the 'c' was "convertible" but apparently it's for "heavy duty chassis."

I just need to know if that LILAND GLOBAL IGM40J which corresponds to Pontiac Part number 411934 and can be seen here: https://www.carparts.com/details/Pon...LILIGM40J.html and that the sending unit REPB670303 (https://www.carparts.com/search?q=repb670303) which corresponds to Pontiac number 6429289 is the correct sending unit. Right now CarParts.com says that both these parts are for the convertible.

The Parts.com site has an answer to a question about size and dimensions that says: "This is a 26 gallon tank with dimensions of 33-3/4" x 31-3/4" x 9-3/8"." It further seems to state that it fits both the 73 Bonneville and the 73 Catalina. And I would have thought that if it fit the Bonneville, it would fit the Grandville.

[michaeld]

Well, this is rather frustrating.

No one knows what gas tank a Pontiac Grandville - which as I understand is a "B-body" car - takes? I'm twisting in the wind here. I can't jack the car up and see where it is currently located, but I need to get the correct parts.

So I found the LILAND GLOBAL IGM40J which corresponds to Pontiac Part number 411934. But I was informed that it is for the convertible only. Although the parts guide I have from December 1972 says it should be for my 73 Grandville hardtop.

Has anyone ever bought a gas tank for a Grandville hardtop?

[madeuce50]

Late to the party but here goes:
A trip thru 1974 and 1983 Pontiac parts books lists the tank for ALL 1973 B-body cars except wagons and H.D.C. [heavy duty chassis] as 495641 and is a 26 gallon tank. The sending unit for 4bbl and or A/C equipped B-body except wagons and H.D.C 1973-1975 in both the 1974 and 1983 parts books is 6429289. There should be no difference between convertibles and 2 dr and 4 dr hardtops in either the tank or the sending unit. Wagons and heavy duty chassis [wagon chassis used for ambulance, hearse and flower cars] use a quarter panel mounted tank, not under the trunk floor. I would be suspect of the applications listed for the LILAND GLOBAL IGM40J as on page 2 of the applications it lists Catalina Safari which is a wagon and if it fits the 2 dr and 4 dr passenger body it absolutely will not work for a wagon. The image they show is for a regular 2 dr/4 dr passenger style under the trunk floor tank, will it fit your application? Can't directly answer that question. But if it fits a convertible it should fit the hardtops, same with the sending unit.