When did the FoMoCo logos change?

[Cobramax]

I have seen at least 3 different FoMoCo logos on alternator stamps and other 60's vintage parts and parts boxes.
Were these logos used simultaneously?   I think there are at least two styles of the rectangular logo.

[Bob Gaines]

I have seen at least 3 different FoMoCo logos on alternator stamps and other 60's vintage parts and parts boxes.
Were these logos used simultaneously?   I think there are at least two styles of the rectangular logo.

It depends on the specific part.They didn't all happen at the same time or even in the same order. For example some fan shrouds transitioned from a FOMOCO in rectangle trademark to a FOMOCO in script inside the oval when typically it is the other way around for other parts.

[98SVT - was 06GT]

I think some of them were for original production line parts and others for ones sold in the service market.
Some of the logos/trademarks started to evolve when Ford became a public traded company in 1956.