New to the mopar world,Need help with 318 build..pleeasse..

Do magnums come with roller rockers, ive heard somwhere,somebody has used chevy roller rockers ,since its not a shaft?,is that doable?whats the best year magnum to find,and by different pushrods,do you mean oil through pushrods,and shorter height?for the dial gauge,how about a dial caliper with the depth meter?is that what your talking about or is that different,thanks for all the responses.