More specifically, will a standard shift flywheel off a 1972 340 work on a 360? Is the balance the same?
Is a 72 340 and a 360 balance the same?
- Thread starter SGBARRACUDA
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Divenut
Well-Known Member
Not sure about manual shift cars. My 72 340 (727) is internally balanced, forged crank etc. I believe later production 340 were cast/externally balanced. I'm sure one of the resident experts will chime in shortly with the scoop.
Pat
Pat
Last edited:
Yes for sure this is a external balance 340.
All 360 were external balance. 72 340 is usually external but some were internal. 340 external balance is specific to the 340.
So then I can assume that the 10236 B&M flex plate won't work with a 72 340 external balanced engine?
Professor Fate
Push the button, Max...
Nope... LATE '72 and all '73 340s had their own specific external balance, different from LA 360s and Magnum 5.9 360s which each had their own specific external balance. None of which are interchangeable with each other or any internally balanced small block.
So I guess putting a 727 behind a late 72 340 requires a specific torque convertor?
Professor Fate
Push the button, Max...
A good convertor shop should be able to balance to the '73 specs. And if I'm not mistaken, there were balance diagrams floating around on how to weight a neutral convertor to the external 340 specs, as well as the 360 and 5.9 variations. Once you find the weight size and location, you just braze it on. MP offered a kit at one time.
Which I guess in turn means I have a 72-73 340 Flywheel/4 speed set up I'll need to sell to the right person.
No the B&M 10236 is not compatible for the external balance 340, the unit you should look at is #10235
B&M Flexplates 10235
B&M Flexplates 10235
Ah thanks.I've not used that B&M part number before
I used the neutral balance B&M plate on a external balance 340 once, back before I knew better. It ran smooth from what I could tell but the car always did eat U-joints some kind of bad. Not sure if thats the reason or not.
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