Converting Used Canon FD lenses for E420

for canon fd it isn't possible because 4/3rds register distance between back of the lens and sensor is 38.58mm and for canon fd register distance is 42mm that makes 3.42mm difference to make an adapter which can't be done while preserving infinity.

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my gear:
E-M5+45mm/1.8
E-520+12-60+14-42+70-300+Sigma 105 + FL-50R+EC20 + SRF-11
and good amount of legacy lenses (list in profile)