Difference from A-body to B-body A833?

Hey guys,

Could someone tell me what the difference is? I always see many A-body a833's for sale, but none for B-bodies. Whats the difference? The linkages? And I really want to convert my 74' Roadrunner to a 4speed.

Thanks.
Funny as I never see a A body ones and only B body and someone sold me one saying it’s was a body and turns out it’s for a B body lol crap