identifying rear-end gear

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rabius75

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i have an 8 1/4 rear end in my car, that, as far as i know, is completely stock. i was hanging my muffler the other day and looked at it, and spotted a tiny tag on the right side (if youre looking from the inspection plate side) that read "2.45" and that was it. it was bolted down with one of the plate covers.
would that be the gear ratio in it? there was another one with some numbers on it, but i couldnt make heads or tails of what it might be.
if thats NOT the ratio, then how can i find out ?
 
*sniff*
but i dont wanna!!!
i mean, DONT WANT THEM!
i bet my car would be so much faster with like, a 3:23
 
yup, you'd notice a pretty big differance even with 3.23s. You can get 3.91s for the 8.25 too.
 
3.91 is a little too high, i was thinking 3.55 would probably be my upper limit. 8.25 is good for like, about 300hp isnt it? if you manage the horses well.
i may just use it if the car i get doesnt have anything better.
i think i could have lots of fun if i put a 3.23/3.55 in my car :wink:
 
The 8.25 will live behind a good amount of power. Especially on street tires.
 
now i need to ID my rear end, im pretty sure it would be an 8 1/4, but i want to confirm it. is there somewhere, without getting inside it, that i can get a series number from to ID it?
 
Look in the tech archives, Theres a rear spotters guide in there.
 
nevermind on the ID... its gotta be a 8.25 or 8.375, because it has 10 bolts. the 8.75 had 9 and they werent exactly evenly spaced...
im looking at a richmond gear online catalog, it shows the gaskets for the inspection plates and tells what years the castings were used. and mine is a 75, the years on the 489 are up to 73.. the 742 is to 68..

it says fits 2.73 ratio and higher carrier... hrmm... 2.73 isnt 2.45
 
it MIGHT, but i really doubt it, just from looking at it...
im gonna figure it out. it wouldnt surprise me a bit if it is a 8.25 because my car is one of the supposed 'super deluxe models.'
after finding the build sheet, it had pretty much every option offered for that year+model.. its weird..
 
it looks JUST like this
8_25.jpg
 
it bubbles out like the second one and it doesnt have a drain plug, and is really round looking.
see, the 7.25 has 9 bolts in it and the 8.25 has 10.
 
i had the same gears in my 7.25,man i could hit like 200 on the freeway,then i put my dads 8 3/4 with 4.56's an man what a diff.it felt like the car wanted to take off to outer space
 
FWIW, if you have an 8.25 with 2.45 gears you will have to purchase a new differnential in order to go to 3.xx gears. In order to make room for the pinion for a 2.45 gear set the diferential is machined differently and won't work with the thicker ring gears in a 3.x gear set.

Also, another quick way to tell which rear end you have is; The 7.25 will have 2 1/2" axle tubes and the 8.25 will have 3".

FWIW, the stock rear end behind a 318 is the 7.25", the 8.25 would have been an option.
 
im telling you guys, its an 8 1/4, and if that was an option, my car has it. ill go find the build sheet for it and look it over again.
 
where would be a good place for me to price rear ends? entire axle setups/housing and 3rd member separately? what width is proper for an a body axle?
 
Used is the cheapest way to go. A complete 8-3/4 will cost you around $800
 
Yup used. I bought a 3.91 geared center for $400. Thats about average price. Then you still need a housing, axles (wich are al small bolt patern stock) Brakes and shock plates.
 
son of a *****.
ok, what if... i get a LSD 8.25 from a newer dakota? :) im not planning on being a hella hot rod anytime soon, so when i have the money to build up a nice 340/360 or whatever, ill probably have the money for a rear end too :)
i think what ill do is use a 318, rebuild it, do some little tricks to the heads and exhaust etc... a mild 318 build up... mebbe for about around high 200 - low 300... and use rear end gear to help my acceleration :) (put the car on a nice diet too, hell, i only weigh like, 145-150... im a skinny guy..)
the sad piece is, im too poor for even that right now. we'll see how it goes, im getting a raise pretty soon from the shop i work during the week, about to put in more hours out there too, so i may have enough money to fund my projects pretty soon. we'll see.
 
Hey rabius,

If you do have a 8.25 and decide you want a set of 3:91's, I have a set. One tooth on the ring gear has a chip out of it but not where it counts. Somebody hit it with a hammer. :roll:

Jack
 
coyote jack, id love it, but im not sure about my rear end right now, it may be of the wrong variety to have gear swap. let me look into it, i may buy them from you, if you can give me a pretty good gaurantee that the chip wont leave me stranded somewhere ... :)
 
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