I have 17 small block rods I'm going to be selling but would like to know what all the numbers and letters mean before I sell them so I know what I have and not advertise something I don't have. I know what the casting number is but as far as the rest of it, I'm lost.
Connecting rod ID
- Thread starter BrooklynA
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3418645 is the forging #. later 318, 360 and 340. 340's will have a bronze bushing in the small end for floating pins.
moparmat2000
Well-Known Member
I have a set of these i just pulled out of a 77 318. Not sure if this helps you. Last time I had 2 sets of stock cast rods out of mid 70s 360s I couldent give em away for the shipping. A set of 8 fits nicely in a medium flat rate box. Ended up loading them in a scrap trailer. You may have better luck than I did. These 8 are destined for the scrap trailer as well.
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Ok. Thank you for clearing it up. I thought they were all 340 rods as they all are bushed. Plus I thought that was the only engines I bothered to save parts from. 7 of them have the hole in them to oil the pins. Mostly wondering if all those other markings meant anything. Didn't think they did but wanted to make sure.
moparmat2000
Well-Known Member
Bushed little end rods are worth saving. The ones I was trying to sell were machined for pressed pins.
Actually they are all worth saving as they are the same forging, not cast. They make a nice HP rod. I used them all the time.
Krooser
Building Chinese Free Engines since 1959...
All Mopar rods are forged not cast.
moparmat2000
Well-Known Member
I will keep this set then.
John Collins
Well-Known Member
I’d buy a set of 8.
Captainkirk
Old School Mopar Warrior
I might be able to help you out, John. I have a set of forged rods from my 340 that I am replacing with forged Eagle rods. Not sure if they are interchangeable with 360 rods, tho...
John Collins
Well-Known Member
They’re the same length. I think the only difference was/is is the 340’s have the bushing for a “floating” pin and maybe the weight?
Captainkirk
Old School Mopar Warrior
One thing to keep in mind, John...the reason I wound up buying new forged Eagles to replace the stock Mopar forged rods was this; I was reluctant to re-use the nearly 50 year old rod bolts yet again. However, when I went to buy NEW ARP rod bolts I was informed that they are a different diameter and require the holes to be align-bored oversize. Doing that and reconditioning the rods came to an estimated $225.00. The new Eagle rods set was $250. No-brainer for me. You can't make this stuff up...
John Collins
Well-Known Member
I knew they’d have to get a little work done on the new bolts, but damn... What Eagle rods?
Captainkirk
Old School Mopar Warrior
Rods: Eagle forged P/N SIR6123CB 6.123 length weight 584g
Note that there are no nuts required on the ARP rod bolts.
John Collins
Well-Known Member
I was looking at those last night... They’re about $350 shipped through Summit. Still not a horrible price for 500hp rated forged rods.
moparmat2000
Well-Known Member
Got my Eagles same PN# thru evilbay $301 shipped with sales tax
Captainkirk
Old School Mopar Warrior
Well, I did buy mine a few years ago; pre-pandemic, anyway. But you are correct; not a bad price. You get new ARP rod bolts included and the fit and finish appears quite nice compared to the factory rods. Bolt them in and fougettaboudit. And It's probably a good assumption that the cost of reconditioning a set of rods has gone up as well. If it was me...well, you already know what I did.
Captainkirk
Old School Mopar Warrior
Also, IIRC, the Eagles weigh roughly 100g LESS than the stockers.
moparmat2000
Well-Known Member
The eagle I beams are rated for I think 500HP 6,000 RPM. Stockers may be nice, and back in the day they were worth reconditioning, and on a full restoration may be nice for guys who want all OEM PN#s , but like my machinest told me, the amount of time he would have to put into a stock set of rods, it's just not worth it. He told me I'd be miles ahead to just buy the eagles, let him balance my rotating assy with them and my KBs and be done with it.
Captainkirk
Old School Mopar Warrior
Same here. It did make me have to pay to have the rotating assembly re-balanced (again) though, because I bought new pistons to go with the rods. Better safe than sorry, I guess.
moparmat2000
Well-Known Member
.030" oversized teener with a forged 340 crank and zero deck pistons
pishta
I know I'm right....
100g less is a huge difference, $75 minimum balance job needed (as far as I have found locally). I would not change rods for a 500HP build, maybe the bolts( Milodon or Pioneer 180k psi...something that would not require a big end rework..yeah I know) . I think money could be better spent on more bang for the buck, ie a pro porting job. I agree on inexpensive rods if you really need them though. Ie you don't have any. Mopar 340 forging floater rods were pretty good stock.
Dartswinger70
Well-Known Member
I would not scrap them. I am of the belief that Id rather use 50 year old Mopar steel than buy overseas cast or forged parts. I'm sure others feel the same I hope.
moparmat2000
Well-Known Member
The only problem I see with the rods other than reconditioning, is cycling. How many times have the originals been run up and down the rev range and "cycled" ? Ya sure they could magnaflux fine today, and in 6 months or a year from now develop a defect because of number of times they have been cycled. Granted new isnt always a guarantee either. But I'd venture a bet it's a better guarantee than older rods with Lord knows how many miles up and down the rev range on them. Better stronger materials used than what was common practice 50 years ago, better bolts, probably better quality control to be able to offer 500HP , and 6,000 RPM. I'd venture to say that's not the absolute limits for these parts, but rather a number assigned to them for reliability reasons.
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Dartswinger70
Well-Known Member
Yes it depends on use, a street cruiser is one thing a high HP race car is another.
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