I recently noticed that on my '83 Z28, the tach only reads up to about 3,000 rpms. Any idea what could cause this? The only mods I have are...MSD cap, rotor, coil, 8.5mm Super Conductor wires, K+N Filter, and my new Flowmaster cat back exhaust.I rev the engine up and the tach needle doesn't move as fast as it should. What do you guys think?

 

Are you using the stock tach or aftermarket.

 

Stock tach. I noticed it after I put my exhaust on. We revved the engine to hear what the car sounded like, now the tach is jumpy.

 

Bad ground, loose wire, or wire brunt/hitting/pinched in the exhaust swap would be my first guess. Check grounds at the back of the heads, check for pinched wires, double check that nothing is hitting the exhaust.

 

could be a damaged wire, or loose ground, but it could also that the tach is bad. my 89 rs had the oppsite problem it read too high.

 

I'm going to check all the wires. I think the problem may lie somewhere near the cap and the coil.

 

NEEDAZ is probably right. When something screws up after doing maintenance or a mod, go back to the last thing you worked on as the problem is most likely related.