hey everyone. i have a stock 305 TBI and am really interested in changing from my 2.73s to 3.42's or 3.23's. i want to keep my drum brakes also. now what i was wondering is what third gens came with 3.23 or 3.42 posi rear ends and had drum brakes.... if any even did lol?and also how hard would the swap be and what would i need?i would really just like a straight swap but i figure theres going to be more to it than that. any advice helps. Thanks!

 

Bump.

 

You'll need to select the gears you want that fit into your long range plans. Then purchase a new ring and pinion set. Plus, you'll need at the least, a mini install kit with a new crush sleeve, shims, and marking compound.

If this is your first gear swap, I'd suggest hiring the job out to a professional shop. Watch, help and learn. Your call.

Good luck

 

There isn't just a whole rear end i can pull out of another car and put on mine?i don't have a whole lot of money to spend on a shop and a rearend.Also i don't really care between 3.23's and 3.42's either one is fine.

 

Sure, you can swap rear ends. That's a great way to go! Keep in mind that if your current set up is drum rears, you want to find a like replacement rear end. Otherwise, a disk brake rear end will also require replacement of the proportioning valve and possible e-brake cables. Also, try to keep it 3rd gen if you want to retain your current rear wheels. 4th gen rears will install just like the 3rd gens but they're a little wider plus the axle bolt pattern differs and your 3rd gen wheels will not bolt up.

 

ok so just one question now. What types of third gens can i get a 3.23 or 3.42 with drum brakes out of? i heard alot of v6's have them but will those axles hold up to a v8?it doesn't have to be POSi but it would be nice if i could find one with POSI.

 

There isn't one person who knows what i can get these gears out of....?

 

There's no difference in strength between the V6 and V8 rears, they're identical to each other. If you're looking for a dirt cheap 3.23 or 3.42, drum rear, then V6 3rd gens are your best friend. Those 2 ratios are pretty much the only ones they got. 3.42's usually came in the 5 speed, V6 cars, and a lot of the automatic V6's got the 3.23's. The only real downside to those rears is posi is almost non-existent in V6 cars. Drum brakes can be found even under the Z/28's. I pulled a non-posi, 3.42 ratio, drum rear out of an 85 Z/28. The only "exotic" things it had was a thick sway bar and aluminum drums. I recently upgraded it with a 4th gen, torsen posi unit, and a set of 28 spline axles, so it's pretty sweet now, and it didn't cost much at all for the parts. Trust me, even a pegleg 3.23 or 3.42 rear will be a VAST improvement over those anemic 2.73's you've got at the moment! You'll be amazed at the difference in get up and go.

 

Right on man thanks!thats good to hear because i know over at our local junk yard we have about 10 v6 third gens. thanks again for the info!

 

http://sethirdgen.org/reardata.htm

Open, review, print out the link above. It'll be valuable to you while your searching for a rear end for your car. Hopefully, the RPO data codes will still be on the printed sticker, found under the console lid.

The 3.23 GU5 RPO drum rear ends are fairly common, holding out till you find one equipped with a limited slip, aka posi G80 RPO, shouldnt be too hard to locate either. Look for a Z28 or Trans Am donar.

Good luck

 

Hey man i am doing the same thing on my car. I bought some very nice used gears and took them down to a shop and their getting me a bearing kit and a few other things but to get it installed and everything good to go its around 500. So its not a hole lot but it is some money.
kevin

 

I did that exact thing with 3.23's when I had an auto RS. It was much more better.......

 

gonna bring this back up to post have another question again. i was at a friends house today and he told me instead of getting a whole rear end out a 3rd gen at the junk yard to just get the gears out of the third member and swap the gears... that confused the hell out of me so is it easier to change the gears like he said or just swap whole rear ends?

 

If you've never tore into a rear before and swapped gears around, it's FAR easier to just swap a whole rear out.

 

There are tools needed to measure backlash, backspacing, etc...
It's not just a matter of tightening a bolt or 2... things have to be measured and calibrated or else it will squeal, wear down and or break soon...

There are also issues of 2 or 3 carrier, going from 2.7 to 3.4 or 3.2 is a different carrier than the other... Do some searches...

That's why someone suggested paying a shop, you don't save much money if you do it twice...

Raf

 

Like the others have said, it's a whole lot easier to change the entire rear end.It will only take you a couple hours even if it's the first rear end you have changed.

 

alright cool. well im just hoping everything comes off easily since its been on there since 1990 lol

 

Like Pat said earlier, V6 cars came with better gears. 1983 and 84 V6 F-Bodies with 700R4 trannies came with 3.23's and 5spd cars came with 3.42's.
All '85-up V6 cars came with 3.42's, regardless of which transmission was used(at least all the ones I've seen in junkyards have been 3.42 cars) When looking for the rear end, look in the glove box and see if the RPO sticker is still in there. If it is, look for RPO codes GU5(3.23's) and GU6(3.42's).

 

We did a similar swap in my car what we did was take a rear end from another firebird that had 3.42 gears and then found posi 3.42 gears out of an s-10 then I took out the non-posi gears and stuck in the posi-gears. You can't just throw them together you have to make sure the gears fit when you put them in make sure that it will spin around so its not to tight and make sure the gears aren't sloppy either. Just go out and buy a shim kit so you are able to adjust the spacing of the gears so they fit. Then stick in the complete rear end that has the posi 3.42 in the firebird housing. That is if you want posi of course.

 

I'll probably want posi eventually because spinning the tires is fun but it will get old after awhile