I want to switch my 87 non tach cluster with one with a tach. What am I am going to run into?

 

IDK what it might take to hook it up. I do know the OE tachometer's are not great. They can be off by 200rpm or more. And that defect fluctuates.
You might be better off getting a good after market tac and finding a place to put it.

 

Thanks. Not terribly concerned about accuracy. I'd just rather know about how its turning rather than watching a gas gauge.

 

Ill tell you what I know, and what I think I know!
1. I have a 87 and plan to eventually do the same. I purchased a dash cluster from, I think it was a 91? but would need to look at it again to see......
2. The pin outs on the 2 plugs are different for each year. So you will need the schematics for both years. ( The 87 never had a tach as an option)
3. 87 has a unique computer, as its the only year carbed, but it used a feedback style carb, and the ignition is controlled through the computer.
4. According to deceased member, Ralph P., the factory tachs are looking for 2 pulses per revolution.
5. your six cylinder is pulsing 6 per revolution.
6. Dakota Digital makes a tach adapter that I believe you can make work.... https://www.dakotadigital.com/index....od/prd1192.htm

I have several notes somewhere and I may be able to supply more info, if I can help.

Good luck and let us know how it goes.

Mine is a little different now. I have a carbed, 2000 5.9 magnum with a HEI (GM style) distributor.