It should be a 9/16, If you are using a socket you need a swivel.
It's hard to get to, don't forget to unplug the 4 wire and to disconnect the battery when you are done to reset the CC
THT
Jim
It's not the wires on the front side of the HEI unit, it'S the wire's coming out from under it(drivers side front) back towards the carb on the passenger side of the HEI. It has to be unpluged to set the timing. When you have it set, plug it back in(turn car off first) then disconnect the battery to zero out the memory on the CC(at lease 10 secs)
reconnect the battery and start it up.
Ckeck out this site...Lot's of good stuff...http://www.flash.net/~rjgeorge/ And Welcome aboard
OK, that sounds easy enough, thanks. Now if only some MORON hadn't broken my windshield with a soccer ball today, things would be good. Don't let anyone tell you differently, Navy bases are full of STUPID people.