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Old 12-02-2019, 08:38 PM
topfuel67 topfuel67 is offline
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Default 1965 Pontiac 326 and 389 crank differences

I have a 65 Pontiac 326 crank. I have looked up the codes and it is the identical specs as the 65 389 crank but the last digit in the part number is 82 instead of 83. Both are Armasteel. Same stroke, mains, rods, snout, and hub specs. Anyways I am thinking about selling the crank as it is in excellent condition, and has just been in my way for years. Is it the same as a 389 which would make it worth selling or is it worth more as a boat anchor?

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Old 12-02-2019, 09:24 PM
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ponyakr ponyakr is offline
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Should be the same except for the balance. Assuming the 389 pistons/rings were heavier than the 326 pistons/rings.

Might require lighter rods & pistons in a 389. It was posted here that if it takes heavy metal to balance, it costs a lot.

But, I don't know any of the details of that deal.

I know that H-beam rods are 760g, which will reduce rod weight a lot. Don't know if that would reduce the total rod/piston weight enuff, or not. Don't know the difference in the factory 326 & 389 piston/pin weight

Probably guys here who can look up the weight of the factory pistons/pins.

Might be a good crank for somebody who is gonna build a hot, stock stroke 389.


Last edited by ponyakr; 12-02-2019 at 09:30 PM.
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Old 12-02-2019, 09:36 PM
tom s tom s is online now
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Good for a 400 also.Tom

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Old 12-02-2019, 09:39 PM
Baron Von Zeppelin Baron Von Zeppelin is offline
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I think they are just a little bit lighter than the 389 crank, is all . iirc

Can be used in a 400 build also.
Folks used to prefer to get the Arma cranks as an upgrade over the 400 Nodular cranks.

They do have a nicer ring to them when struck with a wrench.

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Old 12-02-2019, 09:45 PM
Baron Von Zeppelin Baron Von Zeppelin is offline
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Looks like we all posted about the same time with the same info. lol

I have built two 400's using 326 Arma cranks
Both were balanced by the machine shop, no problems or complications were mentioned or charged extra for.

Stock rods with 0.030+ forged pistons

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Old 12-02-2019, 09:46 PM
topfuel67 topfuel67 is offline
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Thank you for the replies. I will list it in the for sale section.

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Old 12-02-2019, 09:56 PM
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Somebody could also use it to build a screamin 350 !

Built right, with light rods/pistons, should be good to 8000rpm +.

Adam Strang ran 10's with his '68 350HO.


Last edited by ponyakr; 12-02-2019 at 10:06 PM.
  #8  
Old 12-02-2019, 10:03 PM
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With shipping rates becoming more costly, selling 3-3/4” stroke stock cast crankshafts is difficult unless you’re lucky enough to find a local buyer. Most of the time the shipping cost will exceed what you’re able to sell one for.

Honestly they’re not a hot item, tough sell whether it’s a 326 or 389 crank.

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  #9  
Old 12-03-2019, 01:47 AM
topfuel67 topfuel67 is offline
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Hopefully someone who wants to build a high rpm engine can use it. I would hate to scrap it.

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Old 12-04-2019, 08:22 PM
Goatracer1 Goatracer1 is offline
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I used one in a stock rebuild on a 389 back in my younger days. No rebalance and no noticeable vibrations.

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