Hopefully a New cluster swap question!

[SwissArmyJeep]

I've read several pages and several search phrases, and still have a question.
I got a fully gauged cluster to replace my "Idiot lighted monster gas gauge".
My question is:
Would there be any difference in gauges between a 4.0l cluster and a 2.5l cluster?
I know I have to change the temp and oil pres sensors, but will the tach still work correctly with my 4-banger?

[old_man]

The tach will work but will read wrong. Being an EE, I modified mine a few years ago. I think I posted the mod over on MADXJ if they still have it. It must have been 5 years ago.

[SwissArmyJeep]

The tach will work but will read wrong. Being an EE, I modified mine a few years ago. I think I posted the mod over on MADXJ if they still have it. It must have been 5 years ago.
I work in an electronics engineering lab. Can you give me a quick idea of your modification? Resistor, cap?
I looked for your write-up, couldn't find it.
Any help would be apreciated!