Tach not working
 

Hi I have a 1980 Berlinetta with a V6 engine. It had a factory tachometer with a 4500 RPM redline. I replaced it with a used one from a 1979 Z28 (5K redline) both are 7K limit. The tachometer does not operate when the engine is running (it goes to 0 and stays there). I talked to my brother and he said to make sure the TACH wire is plugged in to the distributor.....I checked and it was but the tachometer still doesn't operate.
My thinking is the current tachometer is not compatible with the V6 engine(different firing order). I plan to put a 350 V8 in when I find the right one.


Or are there other issues that I should deal with? Any help would be appreciated.