i have a 1986 trans am ws6 and from what i have already read it seems their was a 85 speedo and possibly a 145mph speedo in these cars. mine has a 145mph speedo which seems to be original since it has 100k miles on it and the car looks and runs like 100k miles. if anyone has information about this please let me know and if you know if their was a lot produces or not thanks.

 

It is a very simple thing to swap, if that's what you're asking.

 

Is it TPI? From what i know the carbed ones came with the 85 speedo. You have the right one in the car, and im pretty sure its the stock one that came in the car new. I drove an 86 Trans Am that had the 145 MPH speedo with only 90K orginal miles on it. Now if it was an early production TPI car i know some came with 85 speedos i believe, but mainly 140 is not very rare or out of the ordinary for an 86.

 

Electric speedos started in firebirds in '86. A mechanical speedo from an earlier firebird would not swap directly over. Not sure how common they are but I have seen quite a few 145 speedos in the yards in TAs, at least for 86 and up. (Mine's an '85 with the 85 mph so I always check). They were available on the carbed motors too, seen a few.

 

The TPI got the 140 Speedo, as did the L69 I have not been through the 1986's but here is the 1987 - 1992 and how they were associated with the Engine, trans and rear gear (some years)

http://www.3rdgenformula.com/all%20y...tachcombos.htm

I want to think that 1986 was the same as 1987, with the addition of the HO (L69) got the same 140 Speedo as the LB9, but with the 5500 redline Tach...