So I put an LT1 in my 89 bird and I keep burning up alternators. The tack only works when the turn signal or brake are on. I know there should be a resistor on the red wire that goes to the alternator, what size should it be and where can I find one?
Thanks for the help

 

Maybe you have a GROUND issue for your tachometer. It almost sounds like when your turn signals are on or brake is on then the tachometer circuit it 'sharing' that ground and thus it begins to work properly. Just a guess.