With the 4.56 gears, the truck is really turning some pretty high RPMs. Bigger tires will help reduce the RPMs some, but I'd like a tach anyway. Anyone install one before? From what I've turned up so far, there is an Autometer one that installs on the alternator but my have some accuracy issues and an Issopro that you glue magnets on the harmonic balancer. Any other product?
You are right, those are pretty much your only options for a 6.2L tach. I've given up on the idea of having one.
With a 6.2L 4.56 gears should only be used with 35" + tires. I was running 3.42's with 31's and it worked well.
I have a couple of 6.2L tach articles I will dig up and send both of you guys, PM me with your email addresses. I will also look in my Hummer service manual, although mine doesn't have it, I know Hummers had an option for a tach.
You can calculate the rpm's, I like to use the calculators over at
www.4lo.com My 6.2 with a th400 and 5.24 gearing used to reall wind out, but installing 42's was like adding an overdrive.