Replace old analog tachometers with new digital tachs

[Classof89]

Has anyone swapped out their old analog tachs, specifically 1989 Gran Sport with 454 Merc inboards, to new digital ones? Is this as simple as just swapping the gauges in the dash or does it require new sensors on the engines or something more?

[COCOLOCO]

Haven't done that - I've got outboards - but I've been reading up on it. first thing you need to do is contact Mercury tech support and give them the s/n of your engine (VIN #). They will tell you if you already have sensors on your engines (or can get sensors/harnesses) that put out a digital signal (which you need for running digital gauges). If you don't, then you'll need to buy an analog to digital NMEA2000 converter. Your analog gages signal wires plug into that converter box, and the output from that converter box will then run your digital gages. So far I've found 3 converter systems: NoLand Engineering, Actisense, and AlbaCombi. That's as far as I've taken it. Each of the websites has tech data and instruction manuals. You'll need to be reasonably well versed in electronics if you want to do a DYI....I'm more of a mechanical guy, so when it's time, I'll find a friend, some cold brews, etc.