Wiring in a tachometer

You will need a 12v gauge. It will hook up the same as the 6v one. You can reuse the wiring if it is in good shape, but you will need a sending unit that matches the resistance of the new gauge. The sender will ground through the chassis and will receive the 12v signal from the gauge. 12v source to the gauge and ground in the dash and sending lead to the tank.

153624
it is absolutely amazing what u can find by using google for
"firing order for a 1951 chevy straight 6"

Can you ground the temp gauge wire and make the gauge move ?
That would tell you if the sending unit is toast.

PROBLEM COULD BE THE WIRING, CHECK WIRING HOOK UP.MAKE SURE WIRING CONNECTIONS IN PLACE GOOD AND TIGHT MAKE SURE FUEL PUMP GETTING GROUND.IF WIRING OKAY.EITHER CAR HAS PCM PROBLEMS.

see if wiring has corroded(injection pump}, check the sensor, add grounding wire. if not replace tachometer with same working voltage

tach hook up for chevy with hei distribitor is 1)white wire ; 12volt source 2)red wire -12 volt ignition switch (+) 3)black wire -battery ground (-) green wire ; to tach terminal on dist. / if it not hei with points just put green wire to neg. (-) side of coil

sounds like you may have melted a wire in the harness someware and you should trace those wires back to see were it is fried.

Purchase a one wire (12 volt) alternator,and install it,and it uses one wire only,the out put wire to the battery from the back of the alternator.Then replace all lamps,and bulbs with 12 volt replacements.Disconnect the voltage regulator completely.The radio,if original,will need a voltage reducer,purchase a coil resister to put in line on the positive input to the radio.This coil resister will reduce the voltage to 7 volts,witch will be fine.The starter will work fine,leave it alone.All dash lights will have to be changed also,to 12 volt bulbs.You can find these replacement parts at any N A P A auto parts store.The resister is a part number irc 13,and the alternator will end in a sw,this means single wire.

autozone

its really easy im not to familiar with that vehicle but it all works the same if it hasd a distributer and a seperate coil or even a dis cap mounted coil either way there is two wires that run into that actual coil all you have to do is tap into them and figure out which way works just pull back the unsulation on the two wires that your tac will come with there might be 3 but one will be a ground and just kinda half way hook it up till you see the tac come to life its really easy just be patient and dont worry if the wires are wrong it wont blow anything up the tac just wont work until you hook it up right 9 times out of 10 when you buy a tach it comes with directions