During my current engine build I discovered some differences between flywheels from the 131 and 130TC Abarth:
Here is a std 130 TC flywheel with a bush in the centre.
Here is the 131 flywheel I am planning to use - the bush is too small to fit into the central hole...
I never thought of measuring this as I thought it would be "plug and play" - not so.
Is there any "system to it" - regarding differences between the flywheels in the Fiat Lancia family?