360 Magnum manual transmission flywheel balance

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lemondana

lemondana

BlackDart
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I recently acquired what i thought was a 92 roller cam LA 360. It's going in my 68 GTS 340 4 speed car. I had purchased one of the Quick Time 71-92 balance weights for the 360. The 360 ended up being a Magnum block, LA heads, oil thru pushrods and an early 360 balancer with the big offset wedge on it. This engine had been a rebuild from someplace. It was out of a 92 pickup with a manual trans. I'm just wondering if it is LA balanced or Magnum balanced. Anyone have any ideas what I need to do? Anyone have a picture and a part number of the Quick Time 360 Magnum balance weight. The one I have is the RM-531.
 
My guess would be that with a magnum short block, you would need magnum balancing. That being said, looks like you have a previously opened and modified engine. I think you need to take it to a machine shop and have them inspect everything and tell you how to balance it correctly
 

We have a 360 here that was built at another shop. We found the shop that built the engine used the 360 damper and then neutral balanced the engine.

This threw us off . Because seeing the 360 damper we assumed 360 flywheel. After making one we ended up using a neutral balance flywheel.

Pull the pan off and look at the crank. Evidence of Balancing front or rear will be noticable. That should give you an idea if it was neutral balance. Look for slugs of heavy metal.
 
The guy still had the truck flywheel and he sent me pictures of it. It has the big 3 drill points on the backside. Does anyone have a picture of the backside of a 360 Magnum flywheel? I'm assuming the drill points would be smaller as the Magnum has a smaller imbalance weight.
 
We used this blue print to make a 360 flywheel. It worked perfect on a externally balanced 360 but not on the engine with the back of the crank neutral balanced. Without looking at the crank all you can do is try either flywheel and see if it has a vibration on a run stand.

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Thanks, I have that diagraghm. The balance on the 71-92 and the later Magnum are different-aren't they? The later Magnum 360 cranks have different casting numbers than the LA.. 360's-right? I guess I'll have to pull the pan off and investigate.
 
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