Slant 6/273 Flywheel Compatibility

Hello FABO,

I have a 1965 Dart currently 225, A833. Originally had a 273 hipo four barrel from the factory.

I’ve slowly been gathering parts over the last couple years to get a small block back into the car. I have a rough looking 1965 273 that I haven’t pulled apart, and a 1978 318 available, that I’m told was rebuilt.

The plan was to bolt a 1964-1965 273 bellhousing (already purchased) with a new 10” clutch. I just recently realized that the slant 6 and 273 flywheels have different bolt patterns.

Has anyone successfully drilled out a slant 6 flywheel to work with a 273? Is this advisable?

Additionally, assuming that I’ll end up needing an original all 273 flywheel—I’m wondering if there are any compatibility issues between that flywheel and the crank in the 1978 318.