Sorry for causing the semi-hijack/confusion guys...
Seco - I picked up a used DM speedcal on the classisfieds to use on mine. It works just fine. installation is easy. It took me a little longer to get mine set right, because my car already had a speedo gear compensating for 3.73s then I put in the 4.10s and it was Waayy off... took a little fiddling with the dip-switches to get the ratio right, but no problems now.