Tach with my 6AL box - Third Generation F-Body Message Boards

chevrolet87 · 10-29-2007, 10:51 PM

I have an 87 Sport Coupe that originally had an LG4 motor in it, we just had a new motor put in it with a full MSD setup. I also just got a 145 speedo out of a 87 and wanted to know how i would wire it. I know there is a plug on the box but would i just run a wire from the back of the tach to there or what. Any help would be greatly appreciated, thanx guys

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Kevin91Z · 10-30-2007, 01:13 PM

The speedo should be a direct swap.

If you hook up the MSD 6AL box according to the directions, your tach should work just fine. However, some carb engines have a "tach filter" on the firewall, which is just a large resister. You will need to either bypass that, or get the tach filter adapter from MSD. I am not 100% sure, so hopefully someone else will reply here.

CamarosRUS · 10-07-2009, 02:01 PM

TTT...

I am going to hook my 6AL again and remember last time the tach acted screwy. I cannot remember if this was with the carb or FI motor, however.

I did convert from FI to carb so I would assume I do not have this tach fiilter on the car.

I'm just trying to get my last JEGS order inline with what I do and do not need.