why not get an old 12 bolt and shortin the axels cut the crap off you don't need have someone weld the stuff you do need and bolt it up. sorry i do not mean to be stupid i guess i'm missing somthing in the process please fill me in

 

you can't shorten a 12 bolt axle ,the splined area is a larger diameter than the rest of the axle, unlike a 9" axle that can be cut and resplined. you'd have to buy factory made axles, but i bet you could get them in what ever length you wanted, or whatever you needed.

 

ahh i see ok well the reason i ask is i'm building a 454 and i have a 10 bolt wich every one tells me wont hold up, so i'm exploring my options guess thats not one of them thanks

 

When you say 10 bolt I assume you're talking about a 7.5 in not the 8.5 in used in f bodies thru 81. If so,it won't hold up but a 10 bolt 8.5 will.My son had an 8.5 in a T.A. with a built 455cuin . Since there are about 4 different 1o bolts[7.5- 7.625- 8.2- 8.5] I think it's less confusing to refer to them by the ring gear size.

 

no reason you couldn't narrow a 12 bolt houseing and buy your axles, or do the same with a 9". i ithnk after you exploe it a little the cheapest thing to do is buy an empty houseing from moser and shop around for the parts to fill it with.

 

Why a 12 bolt?...Is the ring gear size above 8.5" or something?

 

it has the stock 85 z28 rear i think it's 7.5 . i thought the pre 81 would not fit just like the 12 bolts? thats why i was thinking 12 insted of a 10 but if you could tell me how he did the swap that would be great. and i will check out moser to see what they have. thanks for the help jason o and the reason for a 12 bolt is 10 bolts are known to shatter

 

A beefed up 7.5" 10 bolt will survive. I ran high 11's with one and had no problems. If you use a standard transmission or use a transbrake then you risk breaking the teeth off the ring and pinion.

A 12 bolt ring gear is 8 7/8"

You also need to consider that swapping in a non third gen diff requires mounting or finding someway to eliminate the torque arm.

Do like ede said. Buy the housing (also comes with axles) then buy the rest of the parts locally. You should decide on the carrier you want to use first. Standard 12 bolt axles are 30 spline but can be ordered in larger sizes.

 

so the 10 bolt may hold, ya know i happen to have a 86 sc wich i belive has a 3.42 rear would this be to low to use with a th350 or 400? could i just buy axels and a posi? and also could i swap my disc brakes off my other rear and put them on this one?

 

Well I've had I don't know how many cars over the years that came with T-350s or T-400s or 4-speeds, and 3.73s; 69 Chevelle SS396s, 70s Z28s, etc. all came that way. It may not be the most fuel-efficient combo in the world, but it will certainly work. In fact I have a 74 Caprice convertible 454/400 with 3.42s, seems to work OK for me.

No rear end except one for one of these cars (82-up F body) will fit one of these cars, because of the torque arm. You can't just leave that off. In order to use a 12-bolt or a 9-inch or a Dana you have to either replace the stock rear suspension with ladder bars (yuck, if it's a street car) or a 4-link; or provide for the torque arm mount on the rear end housing.

You can do a good bit to stiffen up a 10-bolt... weld the axle tubes, use a girdle type of cover especially one with the braces to hold the caps, use a solid pinion spacer. There are far better axles than stock; the best ones are probably Superior, since they're heat-treated after they're splined, unlike "custom" axles such as Moser or Strange.

I've always had a 10-bolt behind a fairly strong-running 400 SBC in my 83, but since I don't run it at the track with slicks and 5000 RPM clutch dumps, it's held up fairly well (340,000 miles and I'm on my 3rd rear end)

 

Strange makes brand-new 12 bolts for 3rd and 4th gen F-bodys, but they're not cheap.Here's an F-body install:
http://www.pharmacy.arizona.edu/staf...uspension.html

About $2000 with axles and gears, bolts up to torque arm, etc.
-Rich-

 

so the main problem is the torque arm and that the axels are to wide, hmmm i may just buy a welder and a 12 bolt and see what i can come up with, but i'm still going to check out moser cause that sounds like a good idea, also how strong are 12 bolt axels would i need to replace them,

 

sorry stupid question shorter rear shorter axel duh