360 - How can I tell if internally balanced

[sydcuda]

This may seem a silly question, but I'm not sure whether my 360 has been internally balanced or remains externally balanced, as stock. I had the engine built 4 years ago by an out of State engine builder and I cannot remember whether the work involved a full internal balance job or not. I can't get in touch with the builder and he probably wouldnt be able to tell me after all this time, anyway.

Before I fork out the dollars for an external balance 360 flywheel, can I tell just by looking at the crank whether the engine has been internally balanced and therefore I can use the cheaper and more abundant internal balance flywheel? If internally balanced, there would be weights attached to the crank, would there not? Or would I have to pull the rotating assembly and take it to a shop and have them check it.

Any advice greatly appreciated.

 

[dgc333]

The harmonic balancer will have a chunk of extra metal on one side if it's external. Also, if you can see the crank it will have slugs of mallory metal welded into the counter weights if its internal.

 

[sydcuda]

Good point about the harmonic balancer, I didn't think of that. Unfortunately I'm running an aftermarket Romac balancer which doesn't have any visible counterweights on the 360 version, but hopefully I will be able to see a part number and tell if it's a 360 balancer or a neutral balance 318/340 piece. Thanks!

 

[sydcuda]

Actually, problem solved. Found pics of the Romac balancers and they are slightly different between internal and external balance engines. Mine is for a 360 external balance, so I can safely say my engine hasnt been internally balanced (assuming the engine builder did not make a mistake with the balancer!). Thanks again.