1990 318

A cam for Magnums will work just fine in a roller LA, just remember a couple of things:
Magnum cams have a short nose, and can't drive a mechanical fuel pump unless you use an adapter, available from Hughes; or if you specify that you want the cam to be ground on an LA blank.
When choosing a Magnum cam, remember that Magnums have a 1.6 rocker ratio and LAs are 1.5, it will affect your valve lift a proportionate amount.
Lifters are the same part number, roller LA or Magnum.