I still have yet to swap gears in my car, going from 2.92's to a free set 4.11's, I have NO care at all about high rpms on the street, doesnt see much street time. I've heard here and there about the 8.2 10 bolt not being as strong as the 8.5 10 bolt, im sure it is true. What im wanting to know is just what kind of difference im looking at, i have some free stuff, possibly even a locker for the 8.2 (dont forget the free 4.11's), i have a roughly 425hp small block and a 4speed tranny, and im fairly abusive on the clutch, what would be my best bet? put a little money in the 8.2, swap and buy new stuff for an 8.5 (if i can find one), or get a narrowed f..d 9" stuff in some 15 X 10 wheels and slicks for the track and use my regular 15 x 8 for the street ????

I'm pretty sure that you will break that 8.2 with the engine/transmission that you have. You would be better off with a well built 8.5 with 30 spline axles and welded axle tubes.

In order of my preference: built 8.5, 9". That 8.2 will probably go to pieces on you in a very short time if your drive it hard. We have a built 8.5 in our 72 which has a 495 hp sb in it. 2400 stall converter and 4:56 gears. We welded the tubes to the housing, installed Mark Williams axles and c clip eliminators. We also had the posi unit blueprinted by Tom's Differentials in Paramount Ca. We have had no probs yet. The car runs 10.60's.

The ring gear size has alot to do with the stress the ring gear sees as the pinion tries to climb the ring gear (as the front of the car starts to lift on take off). It is kinda like a lever. With this said, the 8.5" ring gear is a longer lever than the 8.2" ring gear. A lot less stress is seen on the 8.5" carrier. Now the stock axles in the 8.2 have the same spline count and are actually interchangable with a stock 8.5 housing. From what I've heard the stock 8.2 rear end is good for 350 to 400 horse power. The stock 8.5 will hold for between 450 to 500. These numbers kinda depend on how well the car hooks up and standard trannies tend to be harder on a rear than Automatic trannies. If your going to use a stock rear the 8.5 is much better than the 8.2. If your going to fork out the cash for changing the axle splines, specialty posi carrier, braces, and everything else your probably better off going with after market 9" or 12 bolt due to the cost. Your current engine will probably destroy an 8.2. You need the 8.5 at least at this time, but if you start adding horses to the engine you may want to look at getting an aftermarket 12 bolt from Mosier or such.

Just my .02

hypotheticaly speaking: what are my chances of making it last till next summer, taking it to the track every other weekend and the occasional trip on the street? keep in mind i am very abusive with a clutch..... is the cost in upgrading an 8.5 anywhere close to the cost of buying a 12bolt? will the 12 bolt stock hold up? or does it need a little bit of upgrading? ive heard the weak part of the 8.2 is the nose where the pinion gear comes out to meet the driveshaft, heard it likes to snap, is this true? can it be braced if someone who knows how to properly weld cast was to put in some braces, at that point would it hold??? alot of questions, but im trying to weigh EVERY option, speaking of EVERY option, im sure this is not even a possibility, but i have a rear from my 62 chevy II from a few years back, im sure it isnt strong enough but ive never heard anything about it so i figured id ask.... already has something like a 4.10 in it......

The nose of the housing is not a problem. The part thi at is likely to break is the ring & pinion gears or the differential (spider) gears. I doubt that it will last long unless you drive it a little on the easy side. I'm not saying that you can't beat on it a little, but regular drag racing with a manual transmission will probably kill it.
I have built several of the 8.5 Nova rear ends and sold them for $1300 complete with a new 30 spline Eaton posi, new 30 spline axles, new gears and all new bearings. I also weld the axle tubes with nickel wire and sand blast the housing. I don't have any cores to build right now, but I should get some around fall.

so...... lets say i run across an 8.5, what are the first things i should do to it to make it more abuse proof...??? most important first...

Take it apart, clen it, sand blast it and take it to a welder who is skilled at welding cast iron. Have him weld the axle tubes to the center casting all the way around. Then get the best quality parts that you can get and have them correctly assembled.

those axles tubes seperate that easy?? with only 425..i think you would need some really good traction to twist or even seperate a tube..just curious

The 8.5 rear ends have very bad plug welds on them. They don't hold up very well at all. If you go to www.nastyz28.com and read about all of the guys who have twisted the tubes in their 8.5 rear ends you will see what I mean. When the tubes twist it puts the yoke and drive shaft into the bottom of the floor. Makes a real mess. The housing is usually scrap after that.

so... welding it together is a MUST, does it need any extra bracing? would upgraded axles be a must as well? or just a really good idea?

The only other bracing that I know of would be to the spring perches. The axle tubes will spin before the stock spring perches will bend, but if you weld the tubes you might as well brace the perches too. Just put some flat pieces of 3/16 sheet metal between the ends of the spring perches and the axle tubes and weld them in place.

As for the axles, the stock 28 spline axles will be the weak link if you build the rest of the rear end correctly. The 28 and 30 spline Eaton posi cost the same, and the 30 spline axles are just $30 more than 28 splines. Chances are that the stock axles will need to be replaced anyway. I have only disassembled 1 of the Nova rear ends lately that had usable axles in it.

makes sense, just for kicks if you have a moment, can i get an "itemized" list of parts, (im thinking spool) i truthfully dont care about streetability at all, but im in the dark on whats good in the differential dept. so id like to know a rough price on each part??? and what all would be recommended.....

Send me an email and I'll get you the prices that you want. biggearhead@bellsouth.net

will do

If it makes any difference at this point in the conversation, I had the 8.2 on my 67 rebuilt and tracked all of the parts/prices I used during the rebuild. It's not exactly stock anymore, except for the case. Everything else has been changed out for better quality aftermarket stuff.

http://www.67chevyii.com/projectlist.htm#differential

Not terribly cheap, but it should handle my car just fine up through 450hp that it may eventually be.

If I wasn't concerned about $$$ and wanted to do it over again, I'd probably build an 8.5" or a 9" next time, but I wanted to retain as much of the original setup as I could safely and keeping the 8.2" made sense.

Hope this was somewhat helpful.
(http://www.67chevyii.com/projectlist.htm#rearsuspension)

Thanks big gear head for the detailed info, but to change in a possible different direction, what all is involved in a 12bolt? does it need upgrading? or can it handle it from the get go? would i maybe be better hunting one down and forking over my wallet? if the 12 bolt is good to go stock then in my opinion it would be worth as much, if not a little more than a completely built 8.5... cause it would be a better starting point............ so... whats the deal with a 12 bolt? does it need upgrading for a 425hp, 4sp, with good traction and an abusive driver? or is it good to go stock????

A GOOD 12 bolt would have no problems with that, except maybe an axle upgrade. The problem is finding one, and paying for it. You would need one from a '68 or '69 Camaro or '68 to '70 Nova. Then there is also the Moser 12 bolt. Send an email if you want details about that one.

what kind of price range would a good used 12 bolt run?

as an after thought.... why from just a '68 or '69 Camaro or '68 to '70 Nova ??? is it a length issue? or is it an issue with them being leaf spring and the others having trailing arm\link arm suspension? ive been planning on doing a ladder bar setup, so, if it is just a suspension issue then it doesnt matter..... just wondering Thanks

The '67 to '69 Camaro and '68 to '7x Nova rear ends are 60 inches wide and have the spring perches 42 1/2 inches center to center. You could narrow an Impala rear end to fit. A GOOD posi 12 bolt for a Camaro or Nova will probably be $1000 to $1500. You might get lucky and find one cheaper.

i thought it was 53" wide, making it a pretty narrow rear end to find..i have a 9" with moser axles and those guys didnt make any access holes for me to reach my retaining bolts man what a pain to get to

You are probably measuring between the backing plates. That is not an accurate measurement because the brakes are different on other rear ends. The only accurate measurement is total width (where the wheels bolt on).

so the only ones that are narrow enough are from the camaro and nova? im not worried about spring pearches or trailing arms, thats all going to be custom on mine, are there any other 12bolts narrow enough???

The '65 to '67 Chevelle 12 bolt is the same width, but they are about as expensive and hard to find as the Camaro 12 bolt. If you are going to build a custom suspension for it, what about a second gen Camaro 8.5 with 30 spline axles, Eaton posi, 3.73 gears already assembled? It's 1/2 inch wider on each end for a total of 1 inch over all. What car is this going in?

Its going in a 77 nova. Id rather put the extra cash into a base 12bolt and have room to upgrade later, as opposed to having a completely built big 10 and having to swap again later, i have plans to "eventually" throw a couple hair dryers on the motor, drop the compression, and have some real fun, but for now i want to have a good starting point...

Then you might want to look at a 9 inch Ford or Dana 60. The stock 12 bolt probably won't hold up to a pair of turbos with traction. You won't want c clip axles anyway. The Moser 12 bolt is a much stronger housing. a OEM 9 inch or Dana 60 could be buit to handle it with after market parts. I don't think a stock 12 bolt would be a good investment for your aplication. Might as well start with something a little stronger.

so....... a moser would be worth the cash in my possible future situation... or a BUILT 9" I have a 9" that is too wide laying in my yard right now, but its leaving as part of a trade for some other stuff..... i can get a 9" housing cheap and if im going to need to upgrade the guts anyway, that might be the way to go??? i think im more confused now than before.....ha ha ha

A Moser 12 bolt would have a better chance of holding up than the GM 12 bolt. A stronger and cheaper way to go would be a Moser Dana 60. It is cheaper than the 12 bolt and has 35 spline axles and a larger ring gear. You can get it with a Detroit Locker or clutch type posi. It's pretty awsome looking under the car too. It would be a bolt in and you could even use your original brakes if you order it right. You'd have to go with the 1350 u joints, which you should do anyway. The 9 inch could turn out to be the same price, or more expensive after you buy all of the parts needed. You would need a case, pinion housing, differential, gears, bearings, yoke, axles and other parts, besides having a housing narrowed.

i was looking at that moser 60, looks like the way to go to me, get a set of 33spline axles for it that way if i do end up throwing down some massive torque i wont risk breaking an axle, i checked out their axle tech section, and it was showing how to pick an axle, and for now id be fine with the 30 spline, but once its being force fed i will need the 33's so id rather do that now than later, so........................ now i just got to find the money!!! somewhere? somehow??

The 60 already has 35 spline axles.

[quote=antihuman81]i was looking at that moser 60, looks like the way to go to me, get a set of 33spline axles for it that way if i do end up throwing down some massive torque i wont risk breaking an axle, quote]

Don't be lulled into a false sense of security. You can build things to take the abuse, but if you abuse anything to often you will break it. This is why most hard core racers are forever rebuilding thier cars between races. It is always a good idea to over build for strength when dealing with weekend warrior racers. Your top level competitors on the other hand have to look at the loss of power vs. the over build. A good example of this is Nascar. Before they made it that the engine you qualify on is the engine you have to race on they were building special engines that were built to only last a little longer than qualifying and then another tougher engine for the race. Now they try and build the engine for everything at the track, qualifying, the race, practice sessions, and Happy hour, but not much more than that becouse every little bit of weight they add in strength costs them a little in power.

i got a little 3 happy on the keyboard there...ha ha i meant 35 spline (i almost just did it again)....... i figure that if im going to spend $1500 every other way, why not get the dana 60 for a little more and have it forever.....

Send me an email if you want more information on the Moser 60.