Differences between a 3100 and a 3400 [Archive] - GrandAmGT.com Forum

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GrandAmMe
10-28-2009, 09:15 PM
Ok,

So my highschool Auto teacher had a 3100 or 3400 engine lying around. I had to remove and replace a Head in a car so I asked if i could work on this one. It was missing a tranny, flywheel, dipstick tube, UIM almost every accessory externally. He doesn't know if its a 3.1 or 3.4. I took of the LIM and Heads today so i was wondering what the differences are? Its missing the UIM so its kind of hard to tell.

Thanks!

Malaclypse
10-28-2009, 11:34 PM
Bore of the cylinders.

If it has twelve bolt-holes for the UIM then its a 3100. If it only has six then it could be a 3100 or a 3400. Its really hard to tell unless you start looking at casting numbers and even then they may be the same. Check out www.60v6.com .

Malibu Glow
10-31-2009, 01:34 PM
Bore of the cylinders.

If it has twelve bolt-holes for the UIM then its a 3100. If it only has six then it could be a 3100 or a 3400. Its really hard to tell unless you start looking at casting numbers and even then they may be the same. Check out www.60v6.com .

Bore will be the difference, but when casting numbers are mentioned will not be the same from a 3100 to a 3400, but unless you have access to a GM book for those numbers it won't do you much good, you might run the numbers through a dealer parts guy and see if they can help with the actual engine size. Or you can do the old method of measuring the bore and stroke of that engine.

AaronGTR
10-31-2009, 02:31 PM
Shouldn't there be something stamped on the block? I don't recall but I could swear I remember seeing LA1 stamped on my 3400 block somewhere. 3100 should have L82 stamped on it. Take a look and see if you find that anywhere. It's worth a try.

GrandAmMe
10-31-2009, 04:36 PM
Damn Aaron your right! Lol i was looking right at that stamp and it said LA1. Atleast im 99.9% sure. I will check. Its a medium sized white sticker with a barcode?

[ChaosweaveR]
10-31-2009, 10:37 PM
Sounds like ya got a 3400 then. LA1 FTW.

AaronGTR
11-01-2009, 07:48 AM
Damn Aaron your right! Lol i was looking right at that stamp and it said LA1. Atleast im 99.9% sure. I will check. Its a medium sized white sticker with a barcode?


I think so yeah. Sometimes it is a silver metal tag too.