Chevy S10 Tach

[JakeNac]

I have a 98 Chevy S10 that I have installed a 383 Chevy into. I kept all sensors and PCM hooked up. It originally had a 2.2 and now the V8. I am using a MSD 6AL with a magnetic pickup distributor no module, just vacuum advanced. What do I need to hook my factory tach? I know which wire is the tach wire from the PCM and I know the PCM is to send 2 pulses per rev. but I don’t know if it is supposed to be square wave 12 volt or???? What does the MSD 6AL put out of the tach send terminal. Recommendations?


Thanks Jake

[msdtech2]

The MSD Tach Output puts out a 12-volt square wave, it will put out 4 pulses per rotation, and so the PCM will have to be modified. I don't know of any company that will do this type of modification.
Thanks,
msdtech2