There seem to be two types of steering arm available here, one which has a U shaped section and claims to be for "pre 1978" cars and another which says it's for "post 78" cars. I'm a little confused as my car is an 84 and yet seems to have the earlier type part. Are they interchangeable? the later type one is a great deal cheaper as it has a flexi joint instead of a seperate bushing on the inside end.