I know this is a Blazer forum, but many of the parts and info interchange with the S10, so I wanted to post this here also.

I have a 92 S10 that started life as a 4.3 TBI. It then went to a true 4.3 Vortec with TBI, and now it is a Vortec 350 with TBI. I just got a set of Sunbird gauges, pigtail, and Typhoon bezel. My question is how do I calibrate the V6 tach for the V8. The cluster came out of 94 Sunbird with the 3.1 V6 (so no boost gauge and only 100mph speedo). I already have the wiring schematics for the regular S10 gauge cluster and for the Sonoma GT (which I think used this cluster anyway).

I searched but have been unable to find a clear answer as to what needs to be changed to calibrate the tach in this application.

Thanks in advance.

PS. I can claim Blazer ownership in the past as my first car was a 83 S15 Jimmy and my second was a 91 S10 Blazer. And now my son has a 92 S10 Blazer (following in my footsteps, maybe?).

 

Doing a search on the web shows that in order to do this there are two ways.

1). find a tach from a v8 and swap it out. Maybe from a silverado.

2). you will need to open the tach and change a component on the circuit board. From my quick searches it seems to be a resister on teh board you need to unsolder and solder the correct one for a v8. But for that trouble it's prob just easier to find one from a v8 and swap them out.