340 engine (flywheel)

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duster 2

duster 2

dustertwo
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just need little guidence here,,,,so Im looking to replace the flywheel on 1972 340 Duster,,,Im finding I need to know if flywheel should be applicable for balanced or unbalanced engine,,,not sure about this,,,I do plan on having engine balanced and line boared
Thanks
 
Look at your dampner, if it is thick with the words USE WITH 340 CAST CRANK ONLY then you need a flywheel for external balanced engines. Most all 72 340's came with forged cranks...
 
duster 2 said:
just need little guidence here,,,,so Im looking to replace the flywheel on 1972 340 Duster,,,Im finding I need to know if flywheel should be applicable for balanced or unbalanced engine,,,not sure about this,,,I do plan on having engine balanced and line boared
Thanks
Click to expand...
And technically, it's not a matter of "balanced" or "unbalanced"- they're all "balanced", just balanced differently; internally or externally.
As HemiSSDart said, you need to look at your harmonic balancer, if it's a cast crank with this balancer, it's externally balanced:
1694270260767.png


1694270294533.png

If it's a forged crank, it is internally balanced and uses this balancer:
1694270418924.png

If it's externally balanced, you need the specific 340 cast crank flywheel, but not the externally balanced LA 360 or Magnum 5.9 flywheel, which are all different.
If internally balanced, any of the internally balanced flywheels will work.
 
If you don't have a dampner then you have to look at the crank, round counterweights mean forged crank, sharp edged counterweights mean cast...
 
McLeod sells a neutral balance flywheel with bolt on weights. The 340 cast is balanced differently than 360 cast cranks don't require as much weight.

Is the motor rebuilt? As others said look at your damper for the "use with 340 cast crank"

I have a flywheel for a cast crank 340 but shipping sould be expensive.
 
duster 2 said:
just need little guidence here,,,,so Im looking to replace the flywheel on 1972 340 Duster,,,Im finding I need to know if flywheel should be applicable for balanced or unbalanced engine,,,not sure about this,,,I do plan on having engine balanced and line boared
Thanks
Click to expand...
What the professor said. Or, if you don't care about originality and want to get rid of those 1.4 year only parts, get a forged crank and neutral balancer during your engine build. That way you'll be able to find replacement parts much easier in the future.
 
I "Believe" all 340 cars with Sticks in 1972
received a forged crank. All the 72 automatics I have
seen had cast cranks.

I seen quite a few = My Mom used to run a very large
Wrecking Yard in So Cal.
 
I had a "72" 340 Automatic transmission Duster with a forged crank. You really just need to look at your crankshaft.
 
Both automatics and manuals had forged and cast cranks in 1972. I had both at one time or another. It's a before and after date, which IIRC was around April 1st 1972.
 
cudamark said:
What the professor said. Or, if you don't care about originality and want to get rid of those 1.4 year only parts, get a forged crank and neutral balancer during your engine build. That way you'll be able to find replacement parts much easier in the future.
Click to expand...
 
HemiSSDart said:
Look at your dampner, if it is thick with the words USE WITH 340 CAST CRANK ONLY then you need a flywheel for external balanced engines. Most all 72 340's came with forged cranks...
Click to expand...
HemiSSDart said:
Look at your dampner, if it is thick with the words USE WITH 340 CAST CRANK ONLY then you need a flywheel for external balanced engines. Most all 72 340's came with forged cranks...
Click to expand...
ok thanks for the info
 
Just neutral balance the cast crank, they are close as is and don't require much. They are lighter than the Forged crank and unless your going to run boost, Nitrous, or doing 8k clutch dums it will take anything the block can withstand.

My 72 cast is internally balanced behind a TKO with a McLeod SFI Flywheel and Jegs SFI balancer, both neutral.
 
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