I just got a new Tach for my truck because I got new gears 4.11 put in and since I run 31" tires, I wanted to see if my RPMs were getting too high on the highway. Anyway, this thing can be set for V4, V6, or V8. I have a 4.9L I6 engine with 5-sp manual transmission. I hooked the new tach to my MSD ignition tach output. However, when I set it to V6, the readings look a little fishy. When I set it to V4, it looks more realistic. Unfortunately, I do not have a V4. And to make things worse, since I've never had a tach in this truck, I don't know what to expect. I would like any feedback from Ya'll. Here is some info I collected.

Setting
6CYL
Ave. RPM. b4 Shiftin'
2k
RPM@65MPH 5th Gear
2k
RPM@75MPH 5th Gear
2.5k

Setting
4CYL
Ave. RPM. b4 Shiftin'
2.5K-3K
RPM@65MPH 5th Gear
3k
RPM@75MPH 5th Gear
4k

I would also be interested in hearing what anyone thinks my red-line point would be. Thanks. I appreciate ANY feedback.

 

Try posting this in the Pre-97 thread...I'm getting ready to put in my beast too, 5spd with no tach...makes sense!