push the cable as tight into the back of the speedo as you can, then push the clip toward the speedo while pulling the cable off. kinda tricky up under the dash, but it can be done. an easier way to do it is to unhook it from the tranny, and pull it thru the firewall with the speedo then unhook it after everything is easy to get at.
1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik