Joined: Mon Nov 28 2005, 12:27PM
Location: motor city
Posts: 65
My 69 fury III has a 8 3/4 rear end in it, does any body know what case numder it would be? it has a open diff in it,I'd like to put a posi unit with a 3.55 gear.
Joined: Mon Oct 10 2005, 01:49PM
Location: Grand Rapids, MI
Posts: 421
If you can get under there and scrape the unit somewhat clean, the numbers are pretty large, just need to look for the last 3, they are the on the side of the snout. Look for XXXXX741, XXXXX742, or XXXXX489.
My guess prolly a 741.
Rebuild kits/Suregrips/lockers/bearings/gearsets are available for all 3 now.
Joined: Mon Nov 28 2005, 12:27PM
Location: motor city
Posts: 65
so the codes are on the left side of housing,Butch I saw the article on your fury that car is awesome, the perfect sleeper. How did you fit the 275 tires under the rear,did you use a different offset wheel. <span class='smallblacktext'>[ Edited Wed Dec 28 2005, 10:17PM ]</span>
Joined: Fri Oct 07 2005, 12:03PM
Location: Central Ky.
Posts: 1575
So at least you know what came in it originally ( if it's still untouched ).
Still could be either a 741-42 or 489 case I guess, only way to be sure is to look. Any of those stumps would interchange if you just want to buy a complete stump & change it for one with a 3.55 & SG. If you are gonna buy a SG & gears & have them installed you do need to know th case #, otherwise it doesn't matter. Only thing to watch is Yoke size, whether you have the small or big joints. ( 7260 vs 7290 ). there is a conversion joint that will adapt between the 2, It's a Spicer unit but I can never remember the # for it. You could just change the rear joint then ( easiest fix ). You can change Yokes but they can get expensive.
Was your's a 318 car? If so, most likely small joint. Even my 383-2 had small joints in it ( still does!).
I have to ask also, Have you looked to make sure it's an 8 3/4 not a 81/4" rear. I just ask cause the 70' Fury III I just parted with a 383-2 had an 8 1/4" under it. I'd never seen one like that but heard they exist. I know Thrashincows ( Brian ) has one under his 70 & it's a 318 car. The numbers experts over ont he other board called it a "turnpike" or some such option? The fact that your sheet calls out either 2.71 (8 1/4) or 2.76 (8 3/4) doesn't really tell ya. Better to know for sure, 8 1/4 has the rear cover plate in case you weren't familiar with them. 8 3/4 is round & solid from the back.
Joined: Mon Nov 28 2005, 12:27PM
Location: motor city
Posts: 65
my car is all original,rear end never been changed, it is round and solid in the back, it is a 383 2barrel. <span class='smallblacktext'>[ Edited Thu Dec 29 2005, 03:32PM ]</span>
Joined: Mon Nov 28 2005, 12:27PM
Location: motor city
Posts: 65
thats my goal to find a better gear and posi to get this car movin,the gear in it now is cool for highway cruising,but I think a 3.55 will be way better movin this land yacht off the line , lol.I'll give up milage for takeoff.
<span class='smallblacktext'>[ Edited Fri Dec 30 2005, 12:01AM ]</span>
lol.I'll give up milage for takeoff.