Fly wheel

[jl8z28]

What would this flywheel be for 3973458 date F 1 9

[AnthonyS]

What would this flywheel be for 3973458 date F 1 9

I believe that's 3973456

[L16pilot]

The casting number 3973456N is the same as my 70 Z28 dated B190, but there could have been various machining specs to the same casting number depending on application. I believe this same flywheel was used on big blocks (internally balanced) and was 11" diam and the "N" indicated Nodular iron. Also the crank flange image looks to be 350, but not sure if this was the original or a later swap indicator.

Not definitive exactly the application for your flywheel, but I would think '69 SBs that came with an 11" flywheel or BBC.