GM306 vs GM307 fuel tank differences

Status
Not open for further replies.

64nailhead

Goat Herder
Dec 1, 2014
5,659
1
12,059
113
Upstate NY
We are in need of a fuel tank for an '86 Regal that will get a sum and added - no internal tank pump.

What are the differences? I see the the '86 Regal takes a GM307 and an '84 MC takes a GM306. Are they dimensionally the same? Baffled? I understand that EFI tanks that are using an intank EFI pump are not the same as the older, carb'd tanks. But I'm not too concerned about anything internal to the tank other than the sending unit that has the incorporated vent line.

Thanks in advance - Jim
 

64nailhead

Goat Herder
Dec 1, 2014
5,659
1
12,059
113
Upstate NY
It'll be the filler neck. The GM3 is the one with out a filler neck, listed for both the Regal & Monte.
Hmm? The 306 and 307 are not listed as interchangeable between the '86 Regal and '84 MC - both have the filler neck though - at least according to the source of sources - RockAuto.com hehe. I bought a GM306 for a MC about a year ago and it had a filler neck. But I'm in need of a tank for the '86 Regal and my rock solid 'source' claims that they require different tanks.
 

64nailhead

Goat Herder
Dec 1, 2014
5,659
1
12,059
113
Upstate NY
Not alot of response - anyone know if the tank for an older G, GM306A, will fit into a '86? I'm thinking it's just a baffle difference - carb'd vs EFI motor maybe?
 

jiho

Royal Smart Person
Jul 26, 2013
1,001
508
113
It's like he said -- the difference is the filler neck. The tank is the same, the filler neck is not. If you get one with the wrong filler neck, the gas cap is unlikely to appear where it should, so to speak. Then again, this can also happen with the "right" filler neck. If you buy the tank and filler neck separately you can test fit and bang on it, then solder the neck in once you have it lined up right. Or whatever you want to try instead of solder. Plus you can drill some holes on the topside at the in-tank end of the tube, to help avoid early shutoff at the gas station trying to fill it up (although in my experience stations are inconsistent and will find a way to defeat you no matter what you try to do).

The tank with the baffle for FI is the 307C. Actually a pan. The 307A does not have the pan. Tanks without filler neck are 3C and 3A. You can use the FI tank with a carburetor, just not with the in-tank pump installed as it will impede flow when it isn't powered (ask me how I know).
 
Last edited:
  • Like
Reactions: 1 users
Status
Not open for further replies.

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor