blue streak caps help

So I have searched and searched, and I am trying to find info on big block electronic ignition dizzy caps from blue streak and could only find info on the blue streak CH-409X cap, but not info on the CH-400, visually it appears the ch-409X just got the emission nipple vent thing on top, and the CH-400 didn't, can anyone tell me if that is the only difference between the caps, Also this might sound dumb but can you swap normal electronic ignition SB( pre magnum) and BB caps ?


Thanks,
-Mike

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can anyone tell me if that is the only difference between the caps, Also this might sound dumb but can you swap normal electronic ignition SB( pre magnum) and BB caps ?

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(1) I do not know (2) there are no dumb Q's/yes they are the same