cleanfitty

on GT's (and maybee 5.0 lx's)
87-89 1/2 were 85mph
some 89's were 140
90-93 were all 140's but different due to the airbags, but also didn't have the idiot lights in the bezel, rather they were in the cluster but got rid of the "low fuel light"

as far as I know, the speedometer cable has nothing to do with which cluster is in there as far as 87-89's 85mph or 140mph.

2 kwik

the gear in the trans does

cleanfitty

seriously??? i didn't know that...

tmajikman

I thought the parts inside the speedo is what made the difference in the ability to use an 85 or 140 speedo. I thought the changing of the gear for the speedo cable related to what rear end gears you used...2.73 compared to 3.73

rm78mustangii

So you're saying a 140 mph speedo from a late 89 - 93 would not be calibrated to work in my 88?

raven_ghostwolf

LOL if i was going by all this I would be confused too.. A 140 from 89 -93 can be fitted to your 88 and work fine. The notched corner of the 90 - 93 (If I remember correctly when I was test fitting some) will not show and look fine in your bezel. You can NOT use a pre 90 unit in a 90 - 93. You can swap from the 85 to 140 as the internals of the speedo is designed to work based on the rpm's of the cable. The gear at the transmisson end of the cable is only changed to adjust for rear gear ratio and or tire diameter changes, It has nothing to do with if your using a 85 or 140 mph speedo. I hope I didn't confuse you more.

Bottom line the 140 will work fine in your car!