Upgraded to 280ZX alternator - now tach reads low and headlights don't work!

[240zip]

The title says it.  I got a 280ZX Turbo alternator and did the swap.  I also bought the voltage regulator plug from MSA and carefully read the instructions.  The car works fine ... except for some reason the headlights no longer work and my tach reads low.  My set-up is a Mallory mechanical advance distributor with a Pertronix and MSD 6AL using their tach adapter.  I was working before.  Just prior to me swapping out the alternator the tach starting bouncing.  Everyone said it's likely due to the twin fans on my radiator pulling too much on the 240Z electrical system.  So I made the swap.  The car seems to run much better, but now the tach only goes up to about 1500 RPM despite the engine revving much higher.

 

Any idea would could have happened? 

 

I know doing a remote diagnostic on such a set-up is asking a great deal, but any pointers as to where to start would be great.  Perhaps something simple I overlooked.  The voltage regulator is completely removed from the circuit.  Nothing was hardwired to it. 

 

 

[Pharaohabq]

Not so sure on the Alt/Tach issue.  Check your grounds maybe.  It is the stock Tach right?   

 

As for the headlights,  Check your Fusible links, you might have bumped a wire, or broken one loose.  Aside from that, just check your fuses in the box.   We would recommend upgrading to the MSA 240Z fusebox and relay fix for the headlights. You'll have much brighter lights and probably fix your issue at the same time.