ok first off this is a track car and there is NO cluster harness at all
I researched a little bit and found you can connect to the positive side of the distributor
or you can link up with the ECU PIN OUT

The ecu would be a much closer and cleaner attachment for me but the diagram shows 2 diff
locations for the ignition control module

http://technet.ff-squad.com/wiring.obd1.htm


what wire should I piggy back onto in order for my tach to operate?

 

Based on Honda circuit diagrams:

For 92-94, the engine speed output from the ignition control module goes to both ECM terminal A21 and A22. So, your pick.

For 95, the engine speed output from the ignition control module goes to ECM terminal A21.

 

solid blue wire on driver side under dash