I have an 82 ta with a 85 mhp speedo would like to put 140 mhp from a formula is it just easier to put an autometer in

 

tool me about 1 hour to swap my 85 to 140, hardest part is getting the cable to snap back on

 

Is there any calibration needed when going to the 140?

 

The 82 TA used a cable-driven speedo; the Formulas all had electrically-driven ones, as did every 86 -92 Firebird that had the gauge package. The few 86 and 87 Firebirds with the idiot lights were still cable-driven.

 

no calibration was needed and its pretty accurate according to those speeding things set up on the side of the road that tell you your speed, and starts flashing when you're going to fast.

 

Camaros and Firebirds are two different stories altogether when it comes to this topic. The Camaros kept a cable driven speedometer well into the 140mph speedometer years, whereas the firebird went to an electronic speedometer in 1986 (as mentioned by Petes 84z28). For an 82 T/A with a cable driven speedometer, it is not a simple plug and play swap to a 140 mph electronic speedometer. There is a small company that sells a 160 mph cable driven speedometer that you can swap in to the existing cluster, it's worth searching for on the boards. Another option that I find appealing is to get a cluster from a canadian spec 82-84 firebird that had a 140 kph speedo and recalibrate it for miles/hr. That way you have a face that matches the rest of your gages.