Chevy flywheels

[Jordan Baker]

Hi all

Today I cleaned up the flywheels I have for my engine. The left flywheel (#839754) is the original one that came with the wartime army 216 engine. The right side one (#3705410)is the one that came with the late model 216 I bought to put in my truck. After counting the teeth I found the right side one has 168 teeth making it a 12v flywheel. I’ve been told and read that flywheels and ring gears can easily be swapped around on the Chevy inline six engines.

However when I put the left flywheel one onto my engine,there is a small gap between the flywheel and the crank flange. See the second picture with the red arrows. Furthermore the 6 mounting bolt holes are for smaller diameter bolts then what the crank flange is drilled/threaded for. The dowl pins all line up just fine. If I was to use the early flywheel I would have to drill out the six mounting holes to accommodate larger diameter bolts on the crank. I can’t see that causing any issues. Would the gap between the crank flang and flywheel matter at all?

If I use the flywheel that came with the engine, I’m faced with the ring gear having 168 teeth versus the 139 teeth I need for the 6v starter. These rings gears are not compatible due to a slightly different overall diameter of the actual flywheel. My options would be to remove the 168 teeth gear and have the flywheel turned down to fit the 139 teeth ring gear. The positive of this would be that the flywheel would fit tight against the crank flange and the 6 mounting holes would be correct. I could also use the 11” clutch.