myasylum, the 8 1/4 is holding up great. The sure grip and 3.55's are night and day compared to the 7 1/4 I took out. The tach is mounted on a bent piece of aluminum. I drilled the holes for the tach, then tucked the alum under the dash pad. I didnt want to drill into anything, in case I wanted to turn the car back into stock appearing. I ran the wires through the dash vent.