9" rear end
5th Gear Member
Joined: Jun 2006
Posts: 4,089
From:
RE: 9" rear end
If you have it narrowed, yes it'll fit.
Gears could be anything from 2.73 to 4.56 for a '71 Mach. You'll have to count the revs or gear teeth to know exactly. You could read the axle tag, but it may or may not be accurate.
Gears could be anything from 2.73 to 4.56 for a '71 Mach. You'll have to count the revs or gear teeth to know exactly. You could read the axle tag, but it may or may not be accurate.
5th Gear Member
Joined: Sep 2006
Posts: 2,266
From: Australia
RE: 9" rear end
ok I'm not so familiar with the mach1 but gearing could be anything from 2.78 to 4.11 and not necessarily original.
You may have to reposition the spring locator mounts on the axle housing.
You may have to change the u-joints on your drive shaft as I think the 9" yoke is different to the 8". If your still runnign the orig drive shaft and planning hp upgrades, you may wanna change the driveshaft over altogether.
It should be pretty straight forward but you need someone who knows what they are doing to shorten and move (if necessary) the spring locators so you get the right pinion angles between diff, driveshft and gearbox.
You may have to reposition the spring locator mounts on the axle housing.
You may have to change the u-joints on your drive shaft as I think the 9" yoke is different to the 8". If your still runnign the orig drive shaft and planning hp upgrades, you may wanna change the driveshaft over altogether.
It should be pretty straight forward but you need someone who knows what they are doing to shorten and move (if necessary) the spring locators so you get the right pinion angles between diff, driveshft and gearbox.
6th Gear Member
Joined: May 2005
Posts: 5,736
From: MD/WV
RE: 9" rear end
ORIGINAL: Aussie66Fastback
ok I'm not so familiar with the mach1 but gearing could be anything from 2.78 to 4.11 and not necessarily original.
You may have to reposition the spring locator mounts on the axle housing.
You may have to change the u-joints on your drive shaft as I think the 9" yoke is different to the 8". If your still runnign the orig drive shaft and planning hp upgrades, you may wanna change the driveshaft over altogether.
It should be pretty straight forward but you need someone who knows what they are doing to shorten and move (if necessary) the spring locators so you get the right pinion angles between diff, driveshft and gearbox.
ok I'm not so familiar with the mach1 but gearing could be anything from 2.78 to 4.11 and not necessarily original.
You may have to reposition the spring locator mounts on the axle housing.
You may have to change the u-joints on your drive shaft as I think the 9" yoke is different to the 8". If your still runnign the orig drive shaft and planning hp upgrades, you may wanna change the driveshaft over altogether.
It should be pretty straight forward but you need someone who knows what they are doing to shorten and move (if necessary) the spring locators so you get the right pinion angles between diff, driveshft and gearbox.
3rd Gear Member
Joined: Jan 2007
Posts: 682
From: Washington
RE: 9" rear end
I would check to see how much it would be to shorten. I think you will be suprised. I was. I was talking to a local shop that wanted $600 to shorten mine. That would make your $200 rear a quick $800. I waited a little longer and found a Granada disc rear for $400. If it has 28 spline axles I don't think they can be shortened and you would have to buy new ones. Anyway, it is worth a call to someone locally.
5th Gear Member
Joined: Sep 2006
Posts: 2,266
From: Australia
RE: 9" rear end
ORIGINAL: baddog671
Mine is 2.73, I think colorado is right..[8D]
ORIGINAL: Aussie66Fastback
ok I'm not so familiar with the mach1 but gearing could be anything from 2.78 to 4.11 and not necessarily original.
ok I'm not so familiar with the mach1 but gearing could be anything from 2.78 to 4.11 and not necessarily original.
Is your's pretty lazy off the line?
I did a basic calc on the 4.56...top speed at 5500rpm is only bout 90mph (give or take different wheel sizes etc). Man it would wanna get there fast[&:]
good point that 68efi makes...axles required for the swap.