I need help replacing camshaft in tr8? actually a tr7 w/a sd1 im about to put in?

i have a 1980 rover sd1 3.5l 215 which is the same motor as a 1961-63 buick 215, Alot of the parts are compatible. i bought i buick 215 complete gasket set and all gaskets fit perfectly. i also bought from ebay " 215 BUICK OLDS ROVER ROAD CAM " but when i went to put the cam in, it had alot of wobble/space between the highest points on cam and the first cam bearing. the cam bearings do need to be replaced, it was more of a mock install just to see if the part would work. are the cams not at all compatible or are my bearings so worn? its alot easier and cheaper to buy a buick 215 cam and bearings than a rover sd1 or tr8. so hopefully Buick's will work. should i buy cheap buick cam bearings to see if they will fit as a Replacement and if they do a buick cam will fit for sure? any other pointers with tr7 v8 conversion w/sd1, i need a bellhousing mainly. im almost going to get a buick 215 because the bellhousing is easier to find