A quick FYI - watch how you run your speedometer cable if you decide to run headers. I burnt/welded my speedometer cable even prior to having it hooked to the speedometer - did it while breaking in the engine and moving the car during painting (prior to putting in the dash).
Brightside is it wasn't to hard to replace. The jacking the car up & down probably took as much time as the replacement. On a side note - I kind of thought the car was coming off the line slow when I was driving via the tach. Well 0-50 mph was a lot quicker than I thought and 50-100 lets just say it didn't take too long either (I wasn't flooring it at either speed). Glad I fixed the speedometer as I am pretty sure I would probably be getting a ticket driving via the tach. 0-25/35 comes a lot faster than most police would probably be comfortable with.