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-   -   1965 Pontiac 326 and 389 crank differences (https://forums.maxperformanceinc.com/forums/showthread.php?t=836095)

topfuel67 12-02-2019 08:38 PM

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?

ponyakr 12-02-2019 09:24 PM

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.

tom s 12-02-2019 09:36 PM

Good for a 400 also.Tom

Baron Von Zeppelin 12-02-2019 09:39 PM

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.

Baron Von Zeppelin 12-02-2019 09:45 PM

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

topfuel67 12-02-2019 09:46 PM

Thank you for the replies. I will list it in the for sale section.

ponyakr 12-02-2019 09:56 PM

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.

b-man 12-02-2019 10:03 PM

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.

topfuel67 12-03-2019 01:47 AM

Hopefully someone who wants to build a high rpm engine can use it. I would hate to scrap it.

Goatracer1 12-04-2019 08:22 PM

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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