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Author Topic: 340 con rod numbers question  (Read 3398 times)

Offline Rob74dodge

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340 con rod numbers question
« on: June 21, 2009 - 01:01:11 AM »
Hi all,
I have recently purchased a 340 cast date 6-21-67.
I checked the numbers on the rods and found 6 to be 2899496 that is 68-73 340.
I used info from the archives.
2 rods have different #'s 3418645. The list in archives doesn't cross that number. The odd numbered rods are floating like the rest but what are they? Cast,forged?what yr?
I'm a little dissapointed that they are not all the same and that the block was supposed to be std bore and is .040 over but still glad to have stumbled over it to buy.
The crank is still std and a good set of x heads came with it so I'm ok with it. It will make a good street screamer' regardless.
Any numbers crunchers out there?  :wave:
 Thanks!
« Last Edit: June 21, 2009 - 01:22:52 AM by Rob74dodge »

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340 con rod numbers question
« on: June 21, 2009 - 01:01:11 AM »



Offline Topcat

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Re: 340 con rod numbers question
« Reply #1 on: June 21, 2009 - 01:21:39 AM »
Hi all,
I have recently purchased a 340 cast date 6-21-67.
I checked the nubers on the rods and found 6 to be 2899496 that is 68-73 340.

2 rods have different #'s 3418645. The list in archives doesn't cross that number. The odd numbered rods are floating like the rest but what are they? .
Any numbers crunchers out there? 

Casting numbers?  Hard to cross reference to p/n if that's what they are.
If they are, check Galen Goviers little white book on casting numbers.

Your block sounds to be a very early 340 production date. Perhaps the earliest production. The earliest I've heard of so far. 

What is the Can cast number? Big numbers on side of block then a dash. The next number is the can number.  i.e. -6. A low number means your block was the beginning production 340.
Mike, Fremont, CA.


Offline Rob74dodge

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Re: 340 con rod numbers question
« Reply #2 on: June 21, 2009 - 01:28:19 AM »
Where would I find Galen Govier's #'s?
The can cast # is 2780930-340-6
I was wondering how close to some of the first it may be.
Thanks

Offline Topcat

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Re: 340 con rod numbers question
« Reply #3 on: June 21, 2009 - 01:37:06 AM »
Where would I find Galen Govier's #'s?
The can cast # is 2780930-340-6
I was wondering how close to some of the first it may be.
Thanks


Call here.
http://www.galengovier.com/
When you get an answer ask for Helen Waite.

Honestly, I don't have one but I would like to. Good luck on the reply from there.
Mike, Fremont, CA.


Offline Rob74dodge

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Re: 340 con rod numbers question
« Reply #4 on: June 21, 2009 - 01:47:23 AM »
 I took a look at that site. Seems I'm still looking for what rod I have. 3418645 is the # on the rod. I'm concerened that the two different rods weight are not the same.
Thanks for the help.
« Last Edit: June 21, 2009 - 07:06:08 PM by Rob74dodge »

Offline jvike

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Re: 340 con rod numbers question
« Reply #5 on: June 22, 2009 - 01:02:13 AM »
I think my 340 have missmatched rods too.. but I didn't note the casting numbers.. 2780980-340-5. 72 mod engine.
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Offline moper

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Re: 340 con rod numbers question
« Reply #6 on: June 22, 2009 - 11:49:04 AM »
Te rods didnt change a tall. Not by material, sizes, or weight. The part number may have depending on the vendors or whatever. So dont worry about it. Be thankful you dont have any copper rods. those were too bad to be run with noraml bearings, so they would copper coat them to tightent he size to make them useful...lol. I have a 318 that loked like it had swallowed some pennies before...

Offline jvike

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Re: 340 con rod numbers question
« Reply #7 on: June 22, 2009 - 03:16:29 PM »
This is my 340, are these copper rods?
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Offline moper

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Re: 340 con rod numbers question
« Reply #8 on: June 23, 2009 - 12:18:19 PM »
I'm not sure, but I believe they didin't coat the bolts... Yours looks like they did. So I dont know. That is what they look like, but the ones I've seen didnt have a coating over the bolts.

Offline femtnmax

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Re: 340 con rod numbers question
« Reply #9 on: June 23, 2009 - 11:32:23 PM »
These performance engines from back in the day have usually had lots of abuse.  A couple years ago I had a real hassle trying to come up with 8 good rebuildable connecting rods for an engine build I was doing.  Most had the caps angle cut. Went thru 20 rod cores to find 8 good ones.   Now I'm more willing to look at aftermarket rods from known good suppliers.  You still need to inspect them, but they are new, have good bolts, weight matched, and are not hacked up by previous rebuilders.
I know theres lots of purists on this forum, but do you really need mopar connecting rods? 
Phil

Offline Rob74dodge

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Re: 340 con rod numbers question
« Reply #10 on: June 25, 2009 - 05:42:38 PM »
I did some digging and if I'm right the 2899496 I have 6 of are 68-73 340 rod 726 grams. The 3418645 I have 2 of are 74-80 360 or a replacement 318/340/360 rod 758 grams.
Then again a dude selling a set on ebay is saying that the 645 & 2899495 is the same just that the 289945 is a Chrysler pt. # in the Chry pt. catalog for a 340 rod and the 3418645 is the casting number put on the rod.
Really I just want the same strength same wieght set of good 340 rods.
The guy I bought my engine from is trying to help sort it out but if I can't get a matched set I may buy some from Eagle.

Offline moper

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Re: 340 con rod numbers question
« Reply #11 on: June 26, 2009 - 08:23:45 AM »
"weight matched" is a bogus term for the mid grade and cheap rods. They simply arent matched the way builders need them. That is, the small ends and the big ends independantly. The whole rod is "xxx" grams, but the balance that we work with doesnt include the whole rod. So if you're looking for the same weight exactly, by looking at the entire rod weight it's a waste of time. You will need to have any performance engine balanced anyway. Just use whatever rods you have and when the balancing job is performed, they will make sure the weights are matched properly.

Offline Rob74dodge

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Re: 340 con rod numbers question
« Reply #12 on: June 26, 2009 - 05:55:28 PM »
Thanks moper, ya learn something new each day.
I talked to my machine shop about it when I took the goodies and the block over. He said he can mak em' right. Have a good weekend.

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Re: 340 con rod numbers question
« Reply #12 on: June 26, 2009 - 05:55:28 PM »