i just bought a new cluster for my 87 iroc-z 350 TPI 145mph speedo. the new one came from a 305 TBI when i hook it up the tach goes way above normal?? is their something i can change on the tach to make it work right? my original speedo and tach look the same but the new tach hits red a 5000 rpms and my original tach hit red at 5500 rpms? i hope its something simple. also when i put the key in and start it the buzzer never stops??

 

bump please

 

i noticed a yellow box on back of clusters. can i swap this and maybe fix my tach??

 

any ideas?

 

If your original cluster functioned as designed, I'd swap the new speedo head and tach into it. I always recommend the above to avoid electrical gremlins of the sort you mention.

JamesC

 

well i fixed it i just took my old tach out and put it in the new cluster works great now!! i unhooked the black box that makes that ring sound. so no more sound either!! will it hurt anything having the black box unhooked??

 

Great? Not if you still have a problem. Disabling the chime won't hurt, but knowing the system isn't working correctly would drive this **** old fart to distraction.

JamesC

 

i see. would my brake light being on cause the chime to go off? cause my back brakes are blocked off right now which i know is not safe.