Can anyone tell me what the standard rear-end ratio was for a 1980?
I know the rear's been changed to 3.55 in mine, which is, i assume, lower geared than stock. Hence she's definitely quicker 0-60 than the figures i have read for a standard 80, and i'm pretty sure my speedo is a bit "optimistic"!
If i knew the stock rear ratio, I could work out just how many percent my speedo over-reads by....
Cheers!

Hello Theo !
the ratio in my book is 3.07:1
Normand

Cool!
Thanks Norm - hows it going? We havn't spoken for a while..
Then by my reckoning, given that everything else is stock, that means my speedo is going to be over reading by around 13.5% - if i'm seeing 60 on the clock, I'll really be closer to doing 52 mph.
Good for quick launches, but not good for the mpg!

I am working hard on the vette to change the hinge spring's and also new pins and brass bushing,
also I have a problem with my rear suspension and my mecanic told me it is the u-joint and it must be change
now I need help to get that fix I will try to do it myself but no experience well good chalenge for me need the step by step procedure please help .....
Normand

Do you mean one of the u-joints in the drive shafts? If so, the Haynes manual gives a fairly good description of what to do. It doesn't look too hard. I think it would help to have a small press to take out/put in the yokes. A big vice would probably do though. Like i say, i'm assuming you mean the drive shaft u-joints, as i don't know of any others in the rear end......
Best of luck with it!

Hello theo !
it is the u-joint of the 2 half-shaft
Normand

Yes, there's quite good instructions in the Haynes for doing those. I've never tackled them myself though. From what i've read, you have to adjust the camber right out, to allow the most room between the diff flanges and the back of the wheel hub. It seems to be just a matter of undoing the flange nuts and dropping them out.
There must be loads of people on here who have done these --- anyone want to add anything??

I've done it....... well sort of I did one, but as one should have it the other side did not go so well. I pressed mine out using a large socket to press it out in a vice. I've done this on drive shafts and it has worked well, but on the half shaft it didn't. One side everything pressed out fine, the other side i cracked the u-joint cap, which left no means for the socket to press out the u-joint. Turns out that 30 years of undercar debris and water had seized the U-joint into place. So I thought I could press it out from the other side and when I tried this I bent the Yoke on the half shaft because the other side had nothing left to stablize it. Long story. So I spent the money and shipped them to Van Steel down in Florida and had them rebuild them.

Worth the money to make sure they were done right. They will refurbed pieces for $80 to 85 ea. I don't think its that bad considering U-joints will run anywhere from $15 to 22 each. Plus they will blast them clean and epoxy coat everything so it doesn't rust. You can also buy new ones from them for $131 ea.

Good luck

Hi Theo,

I don't know if this will work for you but the way we find the true 60mph mark on our speedo's here is the old "mile a minute" formula. Find a long stretch of highway that has mile markers and vary your speed until it takes exactly one minute to traverse the distance. It's absolutely foolproof but it does require open roads without traffic.

Also, they do make kits to correct speedometer readings. I believe it mounts on the cable itself near the transmission.

Good luck!

Hey Rick
Thanks for the advice! Only problem is, you're lucky to find a stretch of, say, a few miles that isn't swarming with traffic over here in the UK! If you can, then it'll be a twisty country lane, not exactly great for speed trials! Although I've conveniently just fixed my cruise control, so at least holding a decently steady speed is very easy now.
In fact, I reckon the way i'm going to do it is to just work it out from the rpm's. However, my tacho gave up the other day, so i'll be needing a new filter/board/both for that..
Once i've got accurate "rev counting ability" it'll just be a question of multiplying my rpm by some factor to get mph. In top, with the trans locked of course.
This depends on the accuracy of my tacho (should be pretty good) and the accuracy of my measurements of the wheel diameter. These are about 25" +/- about 1/2 and inch. So I should get mph to within a couple of percent, i hope. Just need that bloody tacho working!