changing 85 mph speedo to 140

stng87 · 02-01-2004, 06:47 AM

I am talking about changing just the speedometer in the cluster as I have one from a 93 140 mph cluster. How difficult is this to do? Thanks.

skiwesser · 02-02-2004, 01:08 AM

You can't put the 140 face on a 85mph speedo mechcanism, you have to get a 140mph unit(take the whole thing apart and switch the whole mech that the speedo cable hooks into). I'm not very happy with mine as after getting the 140 mech. $75 on e-bay,
& changing it all out my backlighting looked like crap, could'nd read all the numbers at night & the yellow on the tach was blinding. So I took it all out agian and after cutting off some misplaced plastic light directers and swapping brighter bulbs in some spots & dimmer ones in others it is a lot better but still is pretty crappy. A lot of hassle IMO.

thdrcat · 02-02-2004, 07:19 AM

don't.

i changed my 87's cluster for a 140 and still have wiring problems.

stng87 · 02-02-2004, 04:19 PM

I am not talking about changing just the face, or the whole cluster pullout all-together. I am talking about simply switching the speedometer section in the cluster. Removing the 85 im place of a 140. This must be possible since they sell these seperately.

Ackbar00 · 02-02-2004, 04:35 PM

Prolly the best way is to have BBK do it. It is like 170$, but at least it would work. Try here.

http://www.brothersperformance.com/s...nversions.html

Edit- Hmmm, said it was only 70$

Terrifson77 · 02-02-2004, 08:09 PM

I'm running into a similar situation with my '88 GT resto project. As long as you have the speedo unit (the molded pot-metal mechanism on the back, and the black plastic sheet, you should be able to do it. Try removing the needle (carefully), swap the '87s for the 140 unit, and then carefully peel the black plastic faces off and exchange them. I'm not positive this will work, and it might and up lookin like crap as Skiwesser said, but hey, it's worth a try. Let me know if it works.

Jeff

skiwesser · 02-03-2004, 12:28 AM

Yeah you are right you have to change the speedo unit in the cluster to a 140 mph unit, still those plastic light directors must change with diffrent years because the 140 mph unit's did'nt even come near to some of the bulbs, all i know is mine was not what i expected and the faces were not the prob. (hold a flashlight behind just the face and it was perfect) But once installed and i saw it at night i yanked it out the next day,
I've had it out like 4 times and it as good as its gonna get,
great in the day but at night it looks x-tra ghetto

ps the actual swap is pretty easy & strightfoward
pps what kind of wiring problems everything plugs in nothing to wire but clean all plugs as i had a bad connection and the needles fluctuated on about removal #2

stng87 · 02-03-2004, 03:51 AM

Im going to go out on a limb and say before I do this that it is going to work just fine. I see no reason why switching the speedo would cause any problems. We'll see...

88GT 5pt0 · 02-03-2004, 10:39 AM

What I did was took the instrument cluster to a local shop, they changed the it over to 140mph for $40 then I put reverse glow gauges on there that go up to 140mph, and colored the lightbulbs red with a sharpie (so the needles were red at night). Look in the phone book, mine had a section for speedometers in the yellow pages. However when I drove past one of those signs the cops set up that tells you your speed my speedo was 5mph off, not too bad. It looks great

02-01-2004, 06:47 AM	#1
stng87 Registered Member Join Date: Sep 2000 Location: southern california Posts: 329	changing 85 mph speedo to 140 I am talking about changing just the speedometer in the cluster as I have one from a 93 140 mph cluster. How difficult is this to do? Thanks. __________________ 1987 black with t-tops. Cobra intake, 1.7 cobra crane rollers, gt40p's, bbk shorties, off road h-pipe, Holley adj. fuel pressure regulator, Tremec t-5z, 65mm TB, 4.10's, adj cable, 155lph fuel pump, Ram clutch kit, 3 row motorsport radiator, Chrome cobras17x9 front, 17x10.5 rear, Hurst shifter,Former AOD Semper Fi

02-02-2004, 04:19 PM	#4
stng87 Registered Member Join Date: Sep 2000 Location: southern california Posts: 329	I am not talking about changing just the face, or the whole cluster pullout all-together. I am talking about simply switching the speedometer section in the cluster. Removing the 85 im place of a 140. This must be possible since they sell these seperately. __________________ 1987 black with t-tops. Cobra intake, 1.7 cobra crane rollers, gt40p's, bbk shorties, off road h-pipe, Holley adj. fuel pressure regulator, Tremec t-5z, 65mm TB, 4.10's, adj cable, 155lph fuel pump, Ram clutch kit, 3 row motorsport radiator, Chrome cobras17x9 front, 17x10.5 rear, Hurst shifter,Former AOD Semper Fi

02-02-2004, 04:35 PM	#5
Ackbar00 Rebel Fleet Commander Join Date: Oct 2001 Location: Huber Heights, OH Posts: 1,003	Prolly the best way is to have BBK do it. It is like 170$, but at least it would work. Try here. http://www.brothersperformance.com/s...nversions.html Edit- Hmmm, said it was only 70$ __________________ 1993 Mustang GT, PTK w/ T-64 - My Cardomain Webpage 11.25@123.5 on only 8 psi. 10.84@121 on only 1 headgasket "The Truth is, Your the Weak, and I am the Tyranny of Evil Men!"

02-03-2004, 12:28 AM	#7
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Yeah you are right you have to change the speedo unit in the cluster to a 140 mph unit, still those plastic light directors must change with diffrent years because the 140 mph unit's did'nt even come near to some of the bulbs, all i know is mine was not what i expected and the faces were not the prob. (hold a flashlight behind just the face and it was perfect) But once installed and i saw it at night i yanked it out the next day, I've had it out like 4 times and it as good as its gonna get, great in the day but at night it looks x-tra ghetto ps the actual swap is pretty easy & strightfoward pps what kind of wiring problems everything plugs in nothing to wire but clean all plugs as i had a bad connection and the needles fluctuated on about removal #2 __________________ 88 GT: subs,pullies, 1 3/4 longtubes, flowmasters, AFR 165's,T,F #1 cam,Thyphoon intake, 24# inj., 73mm C&L,65mmT.B., 190LPH pump, Eagle sir rods, forged pistons in a newly rebuilt 306. DYNO TUNED TO 300.97 RWHP 337RWTQ

02-03-2004, 03:51 AM	#8
stng87 Registered Member Join Date: Sep 2000 Location: southern california Posts: 329	Im going to go out on a limb and say before I do this that it is going to work just fine. I see no reason why switching the speedo would cause any problems. We'll see... __________________ 1987 black with t-tops. Cobra intake, 1.7 cobra crane rollers, gt40p's, bbk shorties, off road h-pipe, Holley adj. fuel pressure regulator, Tremec t-5z, 65mm TB, 4.10's, adj cable, 155lph fuel pump, Ram clutch kit, 3 row motorsport radiator, Chrome cobras17x9 front, 17x10.5 rear, Hurst shifter,Former AOD Semper Fi

02-02-2004, 01:08 AM	#2
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	You can't put the 140 face on a 85mph speedo mechcanism, you have to get a 140mph unit(take the whole thing apart and switch the whole mech that the speedo cable hooks into). I'm not very happy with mine as after getting the 140 mech. $75 on e-bay, & changing it all out my backlighting looked like crap, could'nd read all the numbers at night & the yellow on the tach was blinding. So I took it all out agian and after cutting off some misplaced plastic light directers and swapping brighter bulbs in some spots & dimmer ones in others it is a lot better but still is pretty crappy. A lot of hassle IMO. __________________ 88 GT: subs,pullies, 1 3/4 longtubes, flowmasters, AFR 165's,T,F #1 cam,Thyphoon intake, 24# inj., 73mm C&L,65mmT.B., 190LPH pump, Eagle sir rods, forged pistons in a newly rebuilt 306. DYNO TUNED TO 300.97 RWHP 337RWTQ

02-02-2004, 07:19 AM	#3
thdrcat Registered Member Join Date: Jul 2002 Posts: 100	don't. i changed my 87's cluster for a 140 and still have wiring problems.

02-02-2004, 08:09 PM	#6
Terrifson77 Registered Member Join Date: Feb 2004 Location: Mena, AR Posts: 12	I'm running into a similar situation with my '88 GT resto project. As long as you have the speedo unit (the molded pot-metal mechanism on the back, and the black plastic sheet, you should be able to do it. Try removing the needle (carefully), swap the '87s for the 140 unit, and then carefully peel the black plastic faces off and exchange them. I'm not positive this will work, and it might and up lookin like crap as Skiwesser said, but hey, it's worth a try. Let me know if it works. Jeff

02-03-2004, 10:39 AM	#9
88GT 5pt0 Registered Member Join Date: Jun 2003 Location: Chicago Posts: 73	What I did was took the instrument cluster to a local shop, they changed the it over to 140mph for $40 then I put reverse glow gauges on there that go up to 140mph, and colored the lightbulbs red with a sharpie (so the needles were red at night). Look in the phone book, mine had a section for speedometers in the yellow pages. However when I drove past one of those signs the cops set up that tells you your speed my speedo was 5mph off, not too bad. It looks great __________________ My Cardomain Website

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