stock 340 rods

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340 mopar

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how fast can I spin original 340 rods that have been balanced? Will they live through 6800 rpm shifts?
Thanks 340 Mopar8-[
 
how heavy are the pistons that are attached to the piston?
 
With good rod bolts, yes. I would recommend having them magnafluxed, shot peened, bushing them and using floating pins. I suspect they would be good for a bit more than that.
 
I do not have the bob weight right now but they are K.B. silverlight hyperutectic (?) dome top 10.5
Thanks again
 
It seems to me the the cost of to shot peen the rods, new bolts, flashing them and the time and effort you can get a new set for cheaper or about the same cost. I ditched my stock rods in favor of some eagle forged h beam rods (with their ESP armor) using the strongest bolt possible. These rods can handle 1500 HP no problem, plus (with my forged aluminum pistons) this thing will zip to 7500 real quick (but I have a rev limited set at 6400).
 
My my engine was built old school (way back in 1990), high RPM (8000-rpm shift point) and high compression.

My 340 rods are the originals but fully prepped.

21 years and 2000 miles later...... and let me tell you this engine has seen 8k many, many times...... The bottom end is still fine.
 
1970Duster said:
It seems to me the the cost of to shot peen the rods, new bolts, flashing them and the time and effort you can get a new set for cheaper or about the same cost. I ditched my stock rods in favor of some eagle forged h beam rods (with their ESP armor) using the strongest bolt possible. These rods can handle 1500 HP no problem, plus (with my forged aluminum pistons) this thing will zip to 7500 real quick (but I have a rev limited set at 6400).
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No it will not. It will get you a set of chinkese knockoffs that may or may not be good metalurgy. Scat, Pro Comp and the like are ALL made in China. There have been huge issues with the metalurgy coming from there. I would stake my motor's health on a good set of reworked factory Chrysler rods any day of the week rather than junk. I can get rods reworked like I outlined for around 300 bucks. What'd your eagles cost?
 
Yes they will live, with a light piston and good rod bolts (I had a set of JE pistons on stock rods with ARP bolts that I ran to 6500-6800 on a regular basis for 8 years) HOWEVER, why not just get some Scat I-beams and have some peace of mind? The Scats are cheap, forged, and light…couple that with a light piston and you have a cheap high rev potential….but then again, cheap and high rev V8 don’t belong in the same sentence, unless you already have some wicked valve train/heads/etc.
 
This is the biggest thing on building a high performance engine as far as parts go.

New rods are cost effective over stock rods. Use stock rods if you must for the class of racing your doing. Otherwise, new con rods are cheaper and stronger (Not all of them though) than reworked and tweaked OE rods.

The OE rod can and will take alot of RPm and power, but at the cost.....well. like I said above.

Power does have an effect on longevity on any engine part.
 
New rods are nice and all....but here's what I'm trying to get at. I've torn down and assembled a boatload of engines. Torn down a lot of failed ones. A lot. Probably tore my first one down about 1975. I have YET in all that time to see what I could flat out confirm to be a connecting rod failure. I've seen rod bearings burn up and let the big end go. I've seen rod bolts give it up and let the big end go. I've seen pins sieze in pistons and rod bushings and let the little end go. But I have yet to see one single 100% confirmed connecting rod failure. It has always been something else that was an underlying cause. Does that mean factory rods have never failed cause I ain't ever seen one? Course not. BUT, I think as many engines as I've seen that does make a SHO NUFF failed rod somewhat rare. I'm talkin about factory rods here. Scat and Eagle are both made in China. Does that mean they are junk? No. What that does mean to this old boy is, you damn well better have them inspected seven ways to Sunday before you run um. I actually have that done to any rods I plan to run, stock or otherwise. It's good insurance. By the time you spend the money to have new rods magged and inspected, you're up there in price. Unless you're talkin about an expensive American made high end connecting rod, IMO, a reworked factory rod is hands down the better deal, both in durability and price. But that's just one peon's humble opinion. Take it for what it's worth. Nuthin. lol
 
To be realistic about this rod pricing...

Consider where you live and local rates, I just called Mesa Machine in escondido and they charge $100 to do rods 'you bring the bolts of your choice' if not...it's $75

Bolts are $50 + rod work=150+tax


That IS cheaper for me than buying new rods.

location & shop rate are the factors to start looking into.
 
StrokerScamp said:
With good rod bolts, yes. I would recommend having them magnafluxed, shot peened, bushing them and using floating pins. I suspect they would be good for a bit more than that.
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Ummm...340 rods are bushed for floating pins from the factory.
 
lilcuda said:
Ummm...340 rods are bushed for floating pins from the factory.
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Not all of them. Some 72s and 73s were not. I was speakin more in general "small block" rod terms. Without the bushed ones....they are all pretty much the same. Sorry, I shouldda included that.
 
1968FormulaS340 said:
My my engine was built old school (way back in 1990), high RPM (8000-rpm shift point) and high compression.

My 340 rods are the originals but fully prepped.

21 years and 2000 miles later...... and let me tell you this engine has seen 8k many, many times...... The bottom end is still fine.
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Did you do the oil galley mod to make the rod journal last at those RPMs?
 
lilcuda said:
So you can make 1000 hp with a stock block and not split a cylinder wall? I doubt it...
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I have no idea why you quoted me or why you would post such a comment as if I think you could make a 1,000 HP on a stock rod and have it live.

Do not quote me and make dumb statments that may confuse somebody into having them think I made that comment or think that.
 
rumblefish360 said:
I have no idea why you quoted me or why you would post such a comment as if I think you could make a 1,000 HP on a stock rod and have it live.

Do not quote me and make dumb statments that may confuse somebody into having them think I made that comment or think that.
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I took your comment....I THINK how you meant it. In other words.....the more power you make, the less durable the engine might be.....right? I was trying to figure out his comment myself. Feel free to smack me if I was off base. lol
 
Safe! at first base! You nailed it. I have no idea what THAT was all about.
 
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