Well to do it right does cost more then a typical repair. Interestingly there is a thread elsewhere I just saw and I was mentioned as being pricy. What many do not understand, and not just with my work, is the invlovement with the job. Mike( tracdogg) certainly knows this but many others don't.
For example,
Open up any vette magazine or go online and you'll see differentials for exchange or rebuilt for $500-$800. When asked why my work runs $1500 on average it does sound like I'm over-priced. Keep in mind I'm using myself as an example - I'm not fishing for work.
Now let's look at the jobs and see what's up with them. The jobs I see advertised and the jobs I've seen pictures of done from other places are basic to say the least. Some places list out all the parts that come in a master kit to build up the job - I do not. I'll list a master kit period.
Along with a master kit a set of clutches are usually installed and that's a good thing. Now the type of clutch used is not listed and there are 3 for a C2 or C3's - slotted, solid, or fiber. I only use the solids and have nothing good to say about the other 2.
At this point the advertised jobs end for parts. Yokes, R&P, spiders, case, solid sleeve and steel cap(if they even install them) are not included. Add up those costs and labor related to them and you can see the difference. My jobs include Tom's gears, Lone Star yokes, a drain plug, cleaned, blasted, POR15'd, top-coated finish, tuned and polished posi(5 hrs alone). Tom's is the only place I see that does this so you could see what those go for on line. I'm guessing if a local shop or vendor quoted this type of job it would cost close to $3k- maybe more considering what I've been told by guys who were quoted after their unit was at a shop.
Now this is not to say a std rebuild is a bad thing, not trying to PO any vendors out there, it's just not the same job. You get what you pay for. I usually turn down requests for these types of jobs as it's not how I would do it for my own cars. I could probably do a std job like those in the same range, may be less- but it's not what I would want to stamp my name in- which I do.
OK enough of this rant you can look up at the sticky for more info. My point is to think about what you are planning to do. Racing costs a lot of money and breaks parts. I'm not or have ever been a racer but Howard sure would know what should be used in your application and the costs. I don't know any way it could be done cheap- unless you buy the parts and do the work.
Even then, if you went with all the HD parts for a 10 bolt, you would have to fit them. Look at my post on fitting a steel cap on a job I did a few weeks ago, no way it could have been done without a grinder and mill.
Good luck, shoot some brake cleaner on the posi case and clean off the CS hole. Then shoot it again and see if you have any cracks.
:smack
