fj40's up till 83 came stock(yes stock, Aisin or Asco locking was an option) with drive plates, which are the same(size wise) as 91-2(at least) DP's. fj40 DP's are more $$ than fj80 DP's, so that why I say use the fj80. But you can still get fj40 DPs. I think the dust caps are cheaper for an 80...