4speed questions

To my knowledge the bellhousings differ 3 to 4 speed and I believe 67 and later used a bigger flywheel.Earlier ones being for 122 tooth flywheel and the later being 130 tooth flywheel. But in any case, 3 speed bellhousings are for 3 speed only unless they have the dual bolt pattern. Again this is to my knowledge,I'm sure some else may have further input. The first is three speed only,the second is four speed only,the third is both

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