I purchased a new speedometer face for my 1980. Now I am assuming I need to recalibrate eveything so 60 doesn't look like 100 or whatever it will be. What would be the best way to do this? Do I have to do something inside the speedometer or do I get a new gear for the speedmeter cable in the tranny?

The speedometer head should be calibrated to the new face. Usually 1000 rpm on the cable should equal 60 mph. If you change the drive gears, the odometer will be off.

Thanks ken, I know you'd come through. Do I need any special components to do that. Is this something I should leave up to someone else?

The only way to calibrate the head is with a consistant 1000 rpm input. Then you need the correct tools to adjust the head.

This can be done by anyone who does speedo head repair. Sometimes you can find a local parts house that does it. Or you may need to send it somewhere.
Hopkins and Kipp used to do it in Akron, now I need to send them to Electosound on Brookpark Rd in Cleveland. Ask some GM dealers parts departments where they send theirs. Not all parts men will cooperate, they want to send it for you and get a markup. But some will. You may need to try a few to get an answer.