Depends upon whch cam you have, the golden rule is that either the cam or the bushes must have scrolls in the bearing surface to allow oil to lubricate the bush/cam, don't know if there is a problem if both have a scroll but don't see why there would be a problem. As you have an 850 you should not have the additional problem with the thrust washers, on the 72 750s they had tabs which sheared off and entered the oil pump seizing it, on the 850 I would fit bushes with a integral flange so dropping the need for thrust washers, not sure but they may have been the std bush for the 850.