How Fast?

I have a 1988 5.0 liter with an automatic transmission, all stock except the exhaust (Dynomax). The tachometer is working perfectly fine, but the speedometer is not functional at all. My question is this: when I'm cruising on the highway in 4th (Overdrive) and the tach reads 1500 RPM, what speed am I doing? The next time you're out on the highway, could you hold the revs at 1500 and report the speed for me? I'd sure appreciate any help I can get. Generally I just tuck in with a pack of cars and do their speed, but I'd like to know how fast we're going y'know?

Alternatively, could anyone please post tach/gear/speed numbers from their '88 5.0L automatics? Like maybe you dont cruise at 1500, but you know 1750 in 4th is always 115kph... or what have you. Thanks to all.

Shelty

why dont you fix it?

you get pulled over, automatic fix-it ticket... at least here in the states
sounds like your speedo gear gave up the ghost...

FORD TOUGH

You should have it fixed. So someone could tell you how fast you are going they need to know your tire size and rear gear ratio. There is a tag on the cover that will tell you the ratio.

How Fast?

Yes, you are right. It's on the list of fixes. I'm still going to keep driving it while waiting for the shop appointment. Now, just for the sake of argument: if I get pulled over, and I'm sitting there getting... oh say a speeding ticket, and the Officer glances at my speedometer, what do you think the number will read? Zero. Because I'll be pulled over right? So how's she gonna know the speedo doesn't work? Canadian police are not psychic, I think. Thanks for your reply, I'm still lokking for the answer.

How Fast?

Yes, I should have it fixed. Let's put that aside for a moment and tackle your other concern. As I already stated the Mustang is stock. That means for 1988 a 225/60/R15 tire with a 3.55 gear. Please correct me if I am mistaken on those numbers. Alternatively we could throw out the math textbooks and another forum member with a stock 88 could tell me how fast their car is going in 4th at 1500 RPMs. I'm not too hung up on the small variables like driver weight (I'm 240lbs) or which grade of gasoline one might be using... I'm just looking for a close number. Something in the ballpark. Thanks for your post, I'm still looking forward to some real data.

projectresto83

If its completely stock you don't have 3.55's. Should be 2.73's or 3.08's.

FORD TOUGH

If it is all stock fill out this door tag decoder form and it will tell you what your gear is. http://www.mustanggt.org/forms/88decode.htm

How Fast?

3.08's. They're 3.08's.


Really? No one here drives an '88? Or is it that all your speedometers don't work either? How strange.

Five0hFox

I've never had mine over 30mph.

Shelty

I have a '91 and at 2,000 rpms ish I am doing 65... stock gears... in 5th gear... I have a 5 speed...

speedo gears are simply unbolt replace, rebolt...