Hey guys, looking for a little help here. I'm finishing off my buddies 73 Challenger he recently had restored. Beautiful car, full restoration, over 60k invested. It's an original ralleye. I can't make the tach work. The original tach did nothing. I read a lot of info from you guys that these tachs went bad often. I replaced the tach. It now has a slight bump when the key is. It will jump to say 1500 when the engine fires, but then drops right back down to zero. I am a professional mechanic and did a lot of homework already. I can find wiring schematics online which helped out greatly on other issues, but the wiring schematics I'm finding must not be for the Ralleye package because none are showing the tach. Any help you guys could give me would be greatly appreciated.