Speedometer Question

rajones · 10-27-2005, 12:04 AM

I have a 1988 GT with an 80 mph speedometer. Why would they put such a small speedo in a car like this? Anyway my question is, how would I change the speedo to a 120 or 140?

skiwesser · 10-28-2005, 11:17 PM

get a 140 mph speedo from a 89 up mustang and put it in your cluster

Gearhead999 · 10-29-2005, 05:52 AM

It was the federal law back then. They felt that when the speedo read higher numbers, [120 mph, etc], that the driver would be more prone to try and peg it, and/or drive faster. Go figure!!!!

This included motorcycles. Heck, I had a Kawasaki that did 85 mph in second gear !!

rajones · 10-29-2005, 10:17 PM

Ok, if I change the cluster will I have to change the gear in the tranny also?

Gearhead999 · 10-30-2005, 06:57 AM

More then likely yes. Or see how far you're off and figure it out. Some of the Mustang magazines have articles about that every so ofter.

One tooth on the driven gear usually moves it 6 mph or so. If you have too much problem a speedometer repair place can usually help. They calibrate speedo's all the time. Last time I had one done it wasn't that much money.

rajones · 11-01-2005, 11:42 PM

Ok, sounds like I know what I need to do. Thanks for the help guys!

10-27-2005, 12:04 AM	#1
rajones Registered Member Join Date: Feb 2005 Location: Kingsport, TN Posts: 4	Speedometer Question I have a 1988 GT with an 80 mph speedometer. Why would they put such a small speedo in a car like this? Anyway my question is, how would I change the speedo to a 120 or 140?

10-28-2005, 11:17 PM	#2
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Re: Speedometer Question get a 140 mph speedo from a 89 up mustang and put it in your cluster __________________ 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

10-29-2005, 05:52 AM	#3
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Re: Speedometer Question It was the federal law back then. They felt that when the speedo read higher numbers, [120 mph, etc], that the driver would be more prone to try and peg it, and/or drive faster. Go figure!!!! This included motorcycles. Heck, I had a Kawasaki that did 85 mph in second gear !! __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

10-29-2005, 10:17 PM	#4
rajones Registered Member Join Date: Feb 2005 Location: Kingsport, TN Posts: 4	Re: Speedometer Question Ok, if I change the cluster will I have to change the gear in the tranny also?

10-30-2005, 06:57 AM	#5
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Re: Speedometer Question More then likely yes. Or see how far you're off and figure it out. Some of the Mustang magazines have articles about that every so ofter. One tooth on the driven gear usually moves it 6 mph or so. If you have too much problem a speedometer repair place can usually help. They calibrate speedo's all the time. Last time I had one done it wasn't that much money. __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

11-01-2005, 11:42 PM	#6
rajones Registered Member Join Date: Feb 2005 Location: Kingsport, TN Posts: 4	Re: Speedometer Question Ok, sounds like I know what I need to do. Thanks for the help guys!

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