340 identification

Greenmachine225 said

now here’s another question, if it has a cast crank then is it externally balanced or internally, and if externally balanced do I need a external balance flex plate or converter. Guy I bought it from put different pistons in it and says it’s about 10.5:1 comp and that he had the rotating assembly balanced with those pistons, does that make it internally balanced now? Sorry I’m a newbie when it comes to 340s and I just want to make sure I don’t do anything to hurt this engine.

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Like Oldmanmopar said, you need to look at the crank. But, cast 340 cranks need far less to internally balance them than 360's do and I don;t recall there being any mallory set in it. It could be either way. If it we're balanced with the damper, then there might be some lightening holes on the damper too.

My cast 340 crank is internally balanced so I had to get the correct flywheel and damper, which are more common. I'm not sure what the factory did for cast crank auto's flex plate or converter counterweight wise.