input on scat I Beams for 360

Classic Mopar Racing Forum

  1. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    Are they good...do they weigh a lot less than stock rods...I would need press fit pin rods. Looks like they go for 375 bucks
     
  2. XfbodyX

    XfbodyX Well-Known Member

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    They are great rods but be sure they are not too light that it costs you in the balance with the added metal.

    Can you post more on your full application, like piston weight, or what piston?

    Stock 360 crank?

    Scats on the far right, can be 200 grams lighter in trw vs a oem 340 rod.

    You can tell in the second pic which build got the scat rods.

    Also im not sure they make that rod unbushed. The eagle sir I beams that are unbushed are super super hard to find.

    For a stock stroke 360 Jegs has the lower range icons for right at $400 a set which is just a hair more then jinkie hypers.

    DSC02068.JPG

    DSC02067.JPG
     
  3. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    Thanks X. The car is a 74 R Runner 318, 4 speed as it was born. 254 thou miles on it and the rod bearings were like shims. New cast pistons, Scat I beams. The 74 318 uses the bigger 340/360 rod but I have to find the factory listed weight for the rod to order the I beams from Scat. Wish I could get press fit and 3/8 hardware
     
  4. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    Is the far right Jegs
     
  5. XfbodyX

    XfbodyX Well-Known Member

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    You reply is a bit confusing. The rod on the right is the scat lightweight approx 560g trw. 400g big, 160g small.

    The icon forged I mentioned are on jegs.

    Im confused about you mentioning ordering rods, they all come boxed in lots, generally within a gram or two and need little.

    Its hard to find any oem piston thats not pressed for a 360 since most were all low comp, low performance.

    It sounds like you are tying to avoid the balance machine but in reality it would be the best $200 you could spend on your project.
     
  6. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    I first mentoned 360 rod to avoid confusing early lightweight 318 rod. I'm using cast 526P .040. flat tops. The pistons are press pin design
     
  7. BudW

    BudW Moderator Staff Member

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    360's use a longer rod than the 273-340's use. That said, there are a few different (factory) versions of the 273-340 rod.

    I recommend using floating pin rods over pressed-in pins, if there is a choice.
    BudW

    Edit, I just read he is installing a 360 into this car, so disregard earlier notes.
     
  8. XfbodyX

    XfbodyX Well-Known Member

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    All small block rods are the same 6.123 length. What the heck thats small block 101. 318-340 3.31 stroke 360 3.58 stroke.

    But never has a different length rod been in the mix in an la or magnum or even poly,

    The ones I posted are left 340 rod, center 318 rod.

    Good luck Ziggy.
     
    Last edited: Mar 25, 2021
  9. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    The motor is a 74 318 which comes with the larger 340/360 rod as compared to the 273/318 -up till 74 rod which is smaller by comparison. I'd prefer to keep the motor origional as I can
     
  10. XfbodyX

    XfbodyX Well-Known Member

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    Why not just put some arp bolts in your current rods and have them resized?

    That would be the best/easiest most wallet friendly way. Many confuse the smaller rods as being sub standard but people run the smaller rods in as much a 400hp auto trans combos. They never break in the beam area, just the lower rod cap mainly do to the oem rod bolts that come loose. But they are bushed... so thats nixed.
     
    Last edited: Mar 25, 2021
  11. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    Geez, my motor has 254 thou and the rod bearings were like shims. New .040 pistons, new rods or some with way less abuse. Maybe a pick up motor doner. I haven't looked at crank yet. Yeah, it'll get balanced
     
  12. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    I raced smaller rod, 71 318 a lot and always shift my 318's at 6500 which is 6800 and no problem. The rods in this 74 are paper weights -to many miles
     
  13. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    You say this why?

    So I'm thinking that if the rods have been pounded and caused the cap to actually oblong, you can literally fix this super easy, it's the standard fix-it process for any connecting rod. The machinist assembles them, sizes the hole, if it's too big the mating surfaces are cut down slightly, stuff is re-assembled and a new hole is drilled.

    Therefore, back to my question up top...you say they are "paper weights", is it because you sized them up and the cap is severly distorted?

    Eithey way, with the availability of replacement rods being pretty good you can certianly pick up a replacement set. The machine shop that did my machinig charges $25/rod to re-condition, which is all of the above activity.
     
  14. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    Cuz my motor has 254 thou miles on it and considering the availability of that 360 rod, I'll at least find a set with less miles
     
  15. Duke5A

    Duke5A Well-Known Member

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    The Scat rods used to be roughly the same price for a set as it would cost to recondition a used stock set with new bolts. Even after reconditioning you're still left with 40 year old rods with untold miles. With how jacked the supply chains are now though I don't know if it is still the better choice price wise.
     
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  16. BudW

    BudW Moderator Staff Member

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    I have heard the term connecting rod fatigue before and for the price of rods and the potential for failure in a high performance, I would tend to lean towards the new parts. For grandma doing her Sunday driving, then reuse what you have.

    If you know who and how the car was driven those 254k miles, the question might answer itself.
    I tend to drive cars hard, and seen too many rod failures in my life (but not my own)...

    I have driven over a million miles in my life, and so far hadn't experienced a engine failure to date (several were ones I built). Transmissions and differentials, yes, but not an engine. That might have cursed me by saying that, just now...
    BudW
     
  17. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    I agree with you. My stroker is getting a set of H-beam rods.

    Having said that, given the situation today should the OP run into a problem sourcing a new set, the re-con way is a viable alternative.

    I suppose what's missing is a clearer 'intended use' statement on the part of OP, and what are some of the key decision drivers today?

    XfbodyX already pointed out the potential added cost of re-balancing, you really cannot discount this. The current rods can certainly be checked for weight, any shop can do this and you can actually look up plenty of on-line info on how to DIY that job, provided that you have a smaller scale to use.
     
  18. ZieglerSpeed

    ZieglerSpeed Well-Known Member

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    The motor will be balanced. I have the press pin cast origional style pistons and my problem would be finding new press fit rods. The 74, 318, 4 speed, 9 1/4 Roadrunner will be drag raced a lot and a lot of freeway.
     
  19. 80mirada

    80mirada Well-Known Member

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    There are usually sets of reconditioned rods on eBay for sale
     
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  20. Ele115

    Ele115 Well-Known Member

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    If diesel continues to go up, and if it goes the way I think it will, shipping and supply chains will really get truly terrible again. I doubt if it will go any other way. Let's hope I am wrong. Right now, it's not even that good.