I did a search on swapping in a 6000 RPM redline tach from a 6 cyl 82-89, and saw some folks said it didn't work. I did the swap today and it turned out good. You just need to swap the board on the tach from your 8 cylinder onto the 6 cylinder tach. It's pretty easy. Just remove the nuts on the gauge lugs and swap it over. I still need to swap the oil pressure gauge over so it's got the 60 PSI instead of the 80, but that's no big deal. I did verify the tach reading with a scan tool to make sure it was acurate and it was within 50 RPM at 4000 RPM. Just thought I'd pass this along. It sure looks a lot better than that lame 5000 RPM redline tach.

 

Yes, you can swap the faceplate over, that's easy enough to do. Usually that involves removing the needle and recalibrating the gauge though.

 

I didn't think of taking the faceplate off. After swapping the circuit board though, the tach was pretty accurate according to my scantool. Do the needles just pop off?

 

Yes, but they're annoying to get back on correctly. If you were able to do it without removing the needle, that's great. Swapping the circuit board should work fine.