90 hatch converted to manuel with an SOHC vtec swap.. Im trying to take the old 90 cluster out and switch in a 90 cluster with a tach.. When I plug it in, everything seems to work fine except the tach.. Do I need to repin something?

 

you shouldnt need to. solid blue wire is tach try looking for it on the cluster plugs.

 

Remember 88-89 clusters are not compatible in 90-91 cars and/or vice versa (without repinning). The older style cluster is more boxy and the newer style is more rounded.