hi,
i've read about other people having just that problem when they try to fit a `Group 4' joint in place of the squishy plate standard one.
the long and short stem thing isn't the problem here - a long stem rack shaft is over 100mm longer than a short one.
on my Escort i've got a Triumph steering UJ which is easily long enough. the Ford Rally Prep book recommends one from a Triumph Dolomite I think, but i got mine from Rimmer Bros for a Herald. i've just checked on their site and the one they show now is like a miniature version of the Escort one instead of a UJ, but still loads better standard.
Bernie
