833 rebuild questions

just a tailshaft swap away... this is going to be a track only car so i was just thinking if i scattered the internals on one i could at least swap the tailshaft over to the spare to make the next weekends race. the only reason i asked the question was to find out how involved it is to swap them... if the entire transmission has to come apart then id agree its not worth keeping the b body unit, i just didnt know :(