I don't know about 6 V,either,(follow Hotrod Lincoln's advice),but I bought a cheepie from Harbor Freight. I took advice,and Taped the trigger,prior to laying it on the starter. Impossible,for me), to aim the light,and turn the dizzy,at the same time. Much easier to lay the light on the starter,aim at timing hole,hook it,(timing light) up,loosen the distributor,just enough to turn it. If you have a vacuum gauge,dis-connect the line at the bottom of your intake,plumb in your gauge,start the truck,and "Git 'er Done!! It tool me 15 minutes,to set-up the timing light,and vacuum gauge,set the air/fuel mixture,and set the timing! Check your manual. Some years call for 5 degrees B.T.D.C,some years call for 5 degrees after T.D.C.,and others call for T.D.C. Engine runs like new!