My 88 Formula odometer is not working since I bought my car last year. Mine has a factory 120 MPH cluster. My mph has also run about 10 miles slow. So... I found a very nice 140 mph cluster out of another 88 V8 bird on CL and bought it. Guy told me it all worked good - it reads 86K on the odo. My question is will my tach register correctly? My stock tach goes to 6K and the new one goes to 8K? Any ideas before I do the switch or should I just sell the new one on Ebay? BTW - my car is carbureted - no computer / sensor parts left.
Thanks for the help.

 

The tachometer will work just fine, however the speedometer and other gauges may not. The tach signal comes straight from the distributor and as long as both tachs were V8 tachs, the RPM range matters not. Obviously this does not mean that by virtue of installing an 8,000 RPM tachometer your engine is able to spin that fast, trust me it does not. The tach will read correctly however as long as it is installed properly.

What may not work is your oil pressure gauge or the new speedometer. The speedometer is calibrated from the factory using a plastic gear set on the tail housing of the transmission based on the gear ratio and tire size of the vehicle. If the speedometer was off initially, it will still be off with the installation of the new cluster. Check your gear set and transmission speed sensor gear set to ensure they match, you can search for charts on here that will tell you what you need to find both.

The oil pressure gauge and sending unit have to be calibrated to each other, as do the coolant temp sensor and gauge. I would encourage you to replace the sending units for those gages if they are different part numbers based on the donor car's cluster. That is easy to research, just look at rockauto.com for the applicable sending units for each car.

 

Thanks so much for the detailed info. I wondered why my spedo was off in the old cluster - but I do know that the tranny was changed out, that was probably why it was off. I didn't know why the stock oil pressure gauge didn't work, so I put in a mechanical one. But now I know what to do.
Thanks again your answer was really helpful.

Red