318 Flex plate question/ help

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Danco

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I am installing a 1984 truck 318 engine into a 1974 duster with a 727 trans. recently I watched a video on a very popular you tube channel where a 318 truck engine had a bad vibration on a dyno. It was eventually discovered with help of a dodge rep that a truck engine uses a different flex plate than a car engine flex plate. So my question is ,what plate do I use and where can I get it?
Thanks for any info or advice you can give me on the matter.

Dan
 
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I am installing a 1984 truck 318 engine into a 1974 duster with a 727 trans. recently I watched a video on a very popular you tube channel where a 318 truck engine had a bad vibration on a dyno. It was eventually discovered with help of a dodge rep that a truck engine uses a different flex plate than a car engine flex plate. So my question is ,what plate do I use and where can I get it?
Thanks for any info or advise you can give me on the matter.

Dan
Sounds like a 360 externally balanced engine issue not a 318.
 
Yup. Car vs truck isn't what matters. Up until 95 the weights for those engines was on the torque converter, not the flex plate.
In the 70s and 80s the only difference in flex plates was that there were 2 different bolt spacings, I believe it was between 904 vs 727, but there were 2 different size converters on 727s. 11" with wide starter ring gear and 12" converter with narrow ring gear. Hopefully that 727 has the smaller converter for your use in a car most 727s behind big block engines had the bigger converters, you should be good.
 
I am installing a 1984 truck 318 engine into a 1974 duster with a 727 trans. recently I watched a video on a very popular you tube channel where a 318 truck engine had a bad vibration on a dyno. It was eventually discovered with help of a dodge rep that a truck engine uses a different flex plate than a car engine flex plate. So my question is ,what plate do I use and where can I get it?
Thanks for any info or advise you can give me on the matter.

Dan



Flex plates come in 4 variations.

Symmetrical and nonsymmetrical for the crank bolt pattern

then 10" and 11" for the converter bolt pattern


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Truck has nothing to do with the balance... you can even pull a 318 magnum out of a truck and it will work with your '74 flexplate/727
 
First I want to apologize, I just went to the video again and 66valiant is correct. It was a 360 and not a 318. I do really appreciate your quick responses and input. Thanks for y’alls help. I knew you guys would set me right and guide me in the right direction.
Again sorry, I wish I would of paid more attention to the info on the video description.
Thanks for your time and your responses where informative.
Thanks
Dan
 
I advise against using a factory or factory replacement flex plate in any level of performance. I have had two that have had the ears sheer off. The last one had two that sheered off.
I recommend this flex plate BB MOPAR/DODGE/CHRYSLER 440 SFI CERTIFIED FLEXPLATE WITH THREE BOLT HOLES | eBay
It says it's for a big block but it'll work for small block too. It has both bolt hole sizes for 5/16" and 7/16".
 
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