Any real difference between factory 340 and 360 connecting rods?

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dibbons

dibbons

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Casting numbers:
2899496 68-73 340 (floating pin)
3418645 71-80 360 and 76-86 318 (pressed pin)

Are they comparable in weight and strength and application? I believe the 360 rods can be bushed for floating pins. Thank you.
 
To answer your questions: yes, yes, yes. You are correct that 360 rods can be bushed for floating pins. Don't remember who, but there is/are members who have honed the small end out and floated pins steel on steel, no bushing. Never done it myself, can't say good or bad idea.

Others may know more......
 
What kind/type of pistons do you have, or are considering buying? Pistons intended to be full floating, cut for snap rings won't/don't care if the pin is press fit in to the small end of the rod; however if the pistons were/are intended to be semi-floating (pin held by press fit in rod) that lone bushed 340 rod says you would need to have one piston cut for snap rings, doable, but not practical, would be MUCH easier to get one more 360 rod.
 
In my case, the motor I purchased with the odd rod combo has all of the rods bushed and high compression factory style pistons with full-floating pins (all 8).
 
JBurch said:
Then you're good to go.....................
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You can buy a good set of h-beam aftermarket connecting rods brand new for less than $200 on the web. I ordered a set myself and was very impressed. I am a retired Chrysler technician and it takes a lot to impress me with all of the junk parts out there new and used.
 
Chryjoe said:
You can buy a good set of h-beam aftermarket connecting rods brand new for less than $200 on the web. I ordered a set myself and was very impressed. I am a retired Chrysler technician and it takes a lot to impress me with all of the junk parts out there new and used.
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$200 for new H beam rods? Where? Not even for $300 I think. Please show us sir.
 
One thing I can say is there almost all are made in China now
 
To the OP, there is not particular reason to go out and buy a new set of rods unless you just want to spend money and lighten your wallet $200.00 to $400.00 dollars, plus balancing costs.

Granted 7 of one forging number and one of another is odd; form, fit, function is equal. No particular reason to discard them because of the odd match up.

Here's a question, has this engine been apart before? Odd as it seems, it could have come out of the factory that way. God only knows and he ain't sayin.....
 
I can weight a set of speedmaster for you tomorrow....generally stock 340/360 rods weight around 745 gram....I believe the Speedmaster are 680 gram...the lightest H beams I have seen is 630 grams...but have not seen those for sale lately...

I got one set of H beams that are 745 grams....dont remember where those came from
 
70aarcuda said:
I can weight a set of speedmaster for you tomorrow....generally stock 340/360 rods weight around 745 gram....I believe the Speedmaster are 680 gram...the lightest H beams I have seen is 630 grams...but have not seen those for sale lately...

I got one set of H beams that are 745 grams....dont remember where those came from
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So matched to a set of sealed power 116hp pistons and a balance job, that should be a nice light weight assembly for a street 360. The 405 pistons in my engine now are on the endangered species list. I appreciate the info on the rods, 70aarcuda, I will look for it tomorrow.
 
JBurch said:
64,000 dollar question(2x)...........why did you pull it apart? What is the engine?
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The engine is a "hodgepodge" 340 in storage that had small leak in the timing cover behind the water pump (see foto).

DSC00035.JPG
 
fratzog lover said:
So matched to a set of sealed power 116hp pistons and a balance job, that should be a nice light weight assembly for a street 360. The 405 pistons in my engine now are on the endangered species list. I appreciate the info on the rods, 70aarcuda, I will look for it tomorrow.
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Just got a 360 block back from the machine shop...using the 116cp pistons and those 745 gram rods...no balancing.....
 
Valkman said:
H Beam 6.123 2.125 .927 Bronze Bush 4340 Connecting Rods Chrysler 318 340 360 | eBay
They're Speedmasters but they should be fine for a street car
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Wow thats a heck of a deal if they are good. My machine shop guy, who i been friends with for years quoted me a whole lot more than that to rework my stock 360 rods.

Quote was for all the typical stuff one would check and or replace on a used rod thats been cycled over 100k. Shot peen, magnaflux, check for straightness, add ARP bolts, and resize big end. Mine are set up for press fit wrist pins.

Then he explained, its a stock 360 rod. Just because they have been magnafluxed and it currently shows no defects it doesnt mean that one if these rods is not gonna develop one, because they are used rods with a lotta miles on them.

Then he said, for the money i'm gonna have to spend on stock rods, i could just buy new forged ones and be done with it. They make new rods, it would be different if the aftermarket didnt offer replacements, then you would have to rework these.

Now he did all that type of work on a set of 2.2 turbo ll forged rods for a wicked little 300 hp shelby engine i built years ago, but that was because of 2 things. 1 theres no aftermarket support for those engines in the way of better than stock forged rods, and 2 turbo ll forged rods are very hard to find, so he redid what i had.

I like what i see with those speedmaster rods, and will likely pull the trigger on a set. I only plan on 400hp out of a 360 so they should live a long comfortable life in there.
 
NO..they are stock mopar size, the .927 is reference to the width of the big end of the rod, not the pin size. There were selling for 187 dollars and I bought a few sets...

Pin End Bore Diameter (in): 0.984 in.
Big End Width (in): 0.927 in
 
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