try here. http://www.westach.com/ i got one that is six volt 0-3500rpm in 100 rpm increments with a 3" face and a bullet case. doesnt matter if its pos. or neg. ground. nothing fancy to install, just hook one wire to your coil and the other one to ground and your good to go. if you want to hook up the light you can do that too. i mounted it to the steering column and have had it going on three years.