Hello, new to this site here. I have always been a import car guy (sold my 240sx sr20det swapped car)but decided to grow up and got a 68 firebird. It has a 5.3ls swapfrom an 2004 Tahoe already done to it but needs a lot of work, like alot. Question I have is they told me the rear axle is from a 2000 Chevy S10. It does have rear disc but can anyone tell me why they would have put that rear end in there? From what I have found it luckily has the same wheel bolt pattern but uses different lug nuts than the front stock firebird front end. Any help or insight would be appreciated.
I added a picture of the LS swap for the heck of it. Thanks
Welcome. I have never seen that swap completed on a first gen. Someone is always 'working on it' and they never finish. How does it run? I guess they kept the computer as I see fuel injectors. The rear for our cars is pretty hard to find and expensive. The S10 is a leaf spring rear so if the spring perches and spring eye distances are copacetic, it makes for a smart swap. Disc brakes are just the icing on the cake. I know second gen F body rears will fit but need to adjust the perches for the proper fit. They are getting scarce too. I would love to see pics of that rear in place and how it was done. The lug nuts will probably be m12x1.50. GM switched to that size many moons go. Be glad you have 4 wheel disc brakes. That is what all cars should have, yet many don't. I have a 1979 Trans Am rear in my '68 just to get 4 wheel discs. I hope they used a 4 wheel disc master cylinder and combination valve.
Here are some pictures of the rear axle. My first thought way that maybe they would switch to the s10 rear end for a different gear ratio or for a limited slip setup but not familiar with it.
I believe i figured out why they used it. I was able to get ahold of the guy i bought it from which is tough because he speaks mostly Spanish (i had to drive to the Mexican border just to pick this car up). He said they put the s10 rear end in here to get the rear disc breaks and also for the LSD which i believe is called posi track for these rear ends. They did add a brake distribution block and an aftermarket universal master cylinder.
Definitely looks like some Mexican craftsmanship on that car.
YIKES!!!! I guess they went to the junkyard with a tape measure and found whatever would fit. Are those spring perches stock location or moved to fit the bird? According to RockAuto there were two rears available. The 7.5" and the 8.5". Try and find out which one you have. I know nothing about that, or where the code would be, so I can't help. The 8.5 would be the one to have, much stronger than the 7.5. That fuel pump needs some attention too. I hope that isn't rubber hose all the way to the engine. And the brake line T fitting. Air shocks? That brake line is run through what was once some sort of mount. Panhard rod? It will take some work to straighten this all out, but again, if that rear is dimensionaly correct, it is a great thing to have.
The 7.5 has more of a squared of shape to the cover and straight axles tubes that measure 2 3/4" 8.5 uses a round cover and the axle tubes step down from 3" to 2 3/4" right after they exit the pumpkin.
2wd width from WMS to WMS is 54.5" 4wd width from WMS to WMS is 59" Zr2 width from WMS to WMS is 63"
S10 Rear end Ring Gear and Axle Sizes: 1983 to 1992 7.5" ring gear 26 spline axles Available from 1988+ 7.625" ring gear 28 spline axles Available from 1995 and up, 8.5" ring gear 30 spline axles, standard for 98+ ZR2's with rear discs
These are some of the axle RPO codes and should be the same for all GMs with either of these axles.
Rear axle codes can be found on a label attached to the left drivers side door lock post. The code appears as a number or letter/number combination in the 'Axle' column of the label. The axle can also be identified by the tag on the axle differential cover bolt.
I just found this in my 2000 Service Manual. Can someone with a spare rear S10 axle take a look and see if this works?
On top of the right axle tube, near the center is a series of letters and numbers (8): (the X's are the letters/numbers; the 1,2,3,4 under them are there to explain what they mean).
Very true, there is definitely some Mexican craftsmanship on this car but it is an amazing shape as far as the body. No rust. All body lines and panels line up perfectly. Only repair I have found d is in the rear pillar passenger side and they actually did it right with dimple welding in the new sheet metal and then skim coating over it. Thinking maybe the body work guy knew what he was doing and the rest not. They did know enough to swap the intake manifold to an ls1 so the hood could close. Just bought a new steering gear box today to get rid of the old leaking one and also ordered a new fuel line setup. Going to run the steel braided stuff with compression fittings all the way from the fuel rail back to the tank/pump. I am from the import world but starting to see a lot of that knowledge copies over minus compatibility and part number stuff. Thanks for your help so far, it is much appreciated.
Hey Chief, judging but the quality of their work- would you expect the 'mechanics' on this job to be capable of a gear change?
Maybe not the Taco benders, but before it hit the junkyard could have been done. I have done gear swaps on brand new vehicles for dealerships before they sold them.
Obviously the only way to truly know what is inside is to drop the cover and count teeth. But I would trust the codes unless something did not add up. Like a supposed 3:08 rear that made the engine run at 5000rpm in high gear. The high gear ratios I posted would be used with an overdrive transmission with lock-up converter. OP: what tranny is in it? The Tahoe would be a 4L60E four speed with overdrive. As for the great body work vs the shadetree mechanicals, I have never seen a body man who was a good mechanic and vice versa. They are two different skills and it would be a unique person that could do both well. That said, I know many Spanish guys that do incredible body work and painting. They have a really good eye for that. When I was in Ft. Bliss many GI's drove across the border into Juarez for some paint work. One of my buddies from Detroit had a 1970 Bonneville. They not only made it look brand new, they did the interior in leather. Very inexpensive too.
