Suggest you become familiar with Vikki's website. Then you can do your own research.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Now that we know which axle you have, I withdraw my previous suggestion to just put in a posi. I would replace your entire axle.
Besides the posi and new gears, you would need a new carrier to replace your low series carrier.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
What rear end u reccommend??? I heard an 8.5 10bolt from a 70 and up firebird..
Agreed. Much cheaper than a 12 bolt or a custom built (like Moser) setup. But I do not know the specifics on which 8.5 rear fits FGF's as far as spring perch positions and width. I thought the ones out of certain Nova's were the most compatible.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
70 and up Firebird or Camaro will not bolt right in. Get an 8.5" from a 72-74 Nova, Ventura or other similar body GM. If you just want to add a posi just buy the posi carrier for the gears you want to run. Also, I put in an 8.5" from a 72 Nova in mine a while back. You have to shorten the driveshaft by 1 inch. When I went from the BOP to the 12 Bolt all I had to do was change the U-Joint on the rear of the driveshaft as the 12 Bolt yoke was a different size than the BOP one.
Mine is doing fine. I only have the 3:42 gears with a posi. I took out the 12 Bolt with 4:11 gears, as I wanted it to be easier on the freeway. The 8.5" is just a little weaker than the 12 Bolt, as the 12 Bolt is 8.875" I know of guys running in the 10's and pulling the frontend off the ground with an 8.5" I hear that the BOP rear is stronger than the Chevy 8.2", Also with the BOP rear you don't have to use the C-Clip eliminators You should be just fine with your rearend, just put in a posi carrier and the gears you want to run, along with new bearings and seals.
Jim at JD race recently posted here on this site with parts for 8.2 rearends for sale. https://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=279541#Post279541 You can probably contact him and he will give you the whole story behind the different rearends. I was going to originally go for a 8.5 out of a nova also. But, he informed me that they werent a direct fit. If I recall correctly, Jim stated that they are slightly wider, a half inch on each side if I recall correctly. I have bad memory now, so dont take that for gospel You should contact Jim, and he can give you all the ins and outs of the different rearends, he is a pro at it.
There were 3 different ratio 8.2 Pontiac 10bolt carriers for both single track & Safe-T-Track usage High ratio = 2.56-2.78 Mid ratio = 2.93-3.08-3.23 Low ratio = 3.36-3.55-3.90-4.11-4.33-4.56-4.88 Eaton posi for the 8.2 only in Low Ratio
As far as a direct bolt-in rear end where no mods are neccessary, other than maybe a rear u-joint swap, these will all fit; '67-69 Firebird, '67-69 Camaro, 10 & 12 bolt, '68-74 Nova & "X" body clones, Ventura, Olds Omega & Buick Apollo. Most common gear ratios to find are 2.56 to 3.08, but they were offered in 3.23 to 4.10, depending on year/model. Positraction, Limited slip, Safe-T-Track, are just different corporate names for the same thing.
Some 71's used the 8.5 some the 8.2, you'll have to check. All 72-75 used the 8.5. All 76-79 with factory V-8 used the 8.5, the 6cyl. in 76-79's used a 7.5. All will bolt in.
The second gen rears as stated will work but the perches would have to moved in.
For WIW I have a 8.2 with an Eaton and so does my brother. Both cars run about 12.80 in 1/4.
The 8.5 are a bit stronger and you would have a few more gear selections to choose.
The 8.5" I put in my 69 came from a 72 Nova. It bolted right in no problems. They are the same width as the 69 Camaro 12 bolt I took out. The only thing was I had to shorten the driveshaft by 1". The 8.5" came out in 72 and replaced the 12 Bolt
Jim at JD race recently posted here on this site with parts for 8.2 rearends for sale. https://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=279541#Post279541 You can probably contact him and he will give you the whole story behind the different rearends. I was going to originally go for a 8.5 out of a nova also. But, he informed me that they weren’t a direct fit. If I recall correctly, Jim stated that they are slightly wider, a half inch on each side if I recall correctly. I have bad memory now, so don’t take that for gospel You should contact Jim, and he can give you all the ins and outs of the different rearends, he is a pro at it.
I must admit, I messed up and had a bad brain fart on what I said in the above quote, as I went back and read some of the emails from Jim. I for some reason kept thinking Nova rearend but it was a Camaro rearend that we were discussing… sorry about that! Both 67-69 Firebird and Camaro and nova 68-79 have the same exact perch mounting center line of 42 7/16 inch mono or multi leaf. The Firebirds rearends were one inch wider (then 1st gen Camaro) for the better handling and wide track. So if you opt for a 1st gen Camaro rearend, you will have ½ inch difference on each side, which is doable and have known a few folks to use them and I couldn’t tell any difference by looking at the back of the car. You can also use a 70-80 Firebird/Camaro 8.5, but you will have to have the spring perches moved, which is actually what I have and Jim did all the work. Very good info at Jim’s site on the 8.5 and 8.2 BOP rearends http://www.jdrace.com/diff_id/10b85.htm
Just for clarification/confirmation. My rear is from a 1974 Nova and I did the conversion. Was a direct bolt-in fit but driveshaft needed to be shortened. I measured overall width narrower than my 8.2 bird rear by about 5/8 inch overall...which moves the wheel inboard by less than 3/8 inch on each side.
Just for clarification/confirmation. My rear is from a 1974 Nova and I did the conversion. Was a direct bolt-in fit but driveshaft needed to be shortened. I measured overall width narrower than my 8.2 bird rear by about 5/8 inch overall...which moves the wheel inboard by less than 3/8 inch on each side.
I do believe you to be correct craze, very minimal width lost and lots better then a half inch in on each side. Are you measuring from the outside of each brake drum or flange to flange? I believe Firebird 8.2 should be 55 1/4, at least that what has been told to me. And yes, I also had to take one inch off my driveshaft also.
Pretty confident I went outside of drum to outside of drum, since I either believed drums must follow the axle wouldn't interchange, or the Nova rear simply came with better drums and those are the ones I intended to use. It's veen a couple years, but I remember comparing them side-by-side, removed from the car, from every possible angle before doing the install and the width difference was very minimal.
Yea, I am not sure about the drums for a nova, but I would think the drums are the same as the 8.2, at least I know I can use my 8.2 rear end drums on my 8.5 2nd gen firebird/Camaro rearend.
When the original 2.56 in my '69 took a crap I went the 2nd gen route. Found a 3.08 posi out of an '81 WS6 T/A for $250 just 20 miles from home on c/l. A friend moved the perches for me. The u-joints were fine since the donor was a Pontiac. It is working great! The second gen units are a fraction of an inch wider than first gens but not enough to cause serious problems unless you want fatter tires. I'm running 215/65/15's now but there is room for 225's.
does it have discs and does that make a difference in the width?
Originally Posted By Hank350
When the original 2.56 in my '69 took a crap I went the 2nd gen route. Found a 3.08 posi out of an '81 WS6 T/A for $250 just 20 miles from home on c/l. A friend moved the perches for me. The u-joints were fine since the donor was a Pontiac. It is working great! The second gen units are a fraction of an inch wider than first gens but not enough to cause serious problems unless you want fatter tires. I'm running 215/65/15's now but there is room for 225's.
The pictured rear came out of my other car. I have had a lot of people, who are in their mid to late 30’s, (my daughter will be 33 in January) tell me “that a chevy rear won’t hold up.” You would have to be in my shoes to realize how amusing it is when a mid to late 30-year-old schools me on substandard rears. Rather than a story-book, I have a picture book. You ought to see the look on their faces when it’s presented in person!
Yes it has discs. The rear is a litle wider flange to flange and then the extra thickness of the disc as compared to the drum adds another 1/4" on each end. Overall the rear with the discs is less than 1" wider.
Originally Posted By Neill
does it have discs and does that make a difference in the width?
Originally Posted By Hank350
When the original 2.56 in my '69 took a crap I went the 2nd gen route. Found a 3.08 posi out of an '81 WS6 T/A for $250 just 20 miles from home on c/l. A friend moved the perches for me. The u-joints were fine since the donor was a Pontiac. It is working great! The second gen units are a fraction of an inch wider than first gens but not enough to cause serious problems unless you want fatter tires. I'm running 215/65/15's now but there is room for 225's.