Rear gearing

[oldmansmonte]

Seeing as how you have no overdrive, a fairly weak V8(sorry didn't mean in insult) and a desire for highway drive ability, you should probably shoot for 3.07's. There were a ton of the rear ends made for G bodies, I think mostly monte's and Cutlasses, and they might even come with posi. That will at least give you a little more jump when you need it without making the engine scream at 65-70 mph.

 

[DRIVEN]

3.08s? That's a good non-overdrive ratio. Very common ratio in the '60s and '70s.
Mysons80elcamino, it's usually cheaper, faster and easier to just replace the entire rearend than to do a gear change if you have that option. I did a 3.42 posi upgrade in my car using wrecking yard parts with new bearings/seals. If I had been more patient and looked it probably would have been cheaper to swap the entire rearend. Certainly faster and easier. I guess it depends on your timeline and comfort level though. Not everyone feels comfortable setting up rearend gears.

 

[woody31]

i recently found a 3.08 posi in a 4 door g body,,i got the guts out of the posi unit to fix my busted 373 posi unit :lol: ,,went back on a half off sale day but they had smashed it... 🙁
3.08 is a good street gear...on a stock,,or near stock motor and combo,,i would not recommend anything lower,,,cheers

 

[darbysan]

I had 3.08 in my Elky when I bought it. With the TH350c trans, it was OK, but I swapped in a 3.42 rear out of a Monte Carlo SS, and it felt like a new engine. Hwy rev's were between 2700 and 3000, which is the only drawback. If I got that much of an improvement out of .34 additional gear ratio, you should feel a similar (if not better) improvement going from 2.56 to 3.08. An added bonus, if you don't swap rears, is that your Series 2 carrier can still be used.

 

[mysons80elcamino]

so approxamitly how much is this going to cost me. I think I want to get this done soon, it sounds like my son will be happy with the results

I am going to retain what I got and just change the gears and speedo gear correct?

do I need the master rebuild kit also?

 

[DRIVEN]

Don't know. Depends on where you order parts and how much you replace. Have you ever set up a rearend before? Do you have the pullers to replace the bearings? A press to install them? I understand that everyone has to start somewhere but I still think you'll be time/money ahead to just replace the entire rearend.

 

[vonclod]

i was quoted between 350-400 to swap a carrier and properly set up for new gearing, and that includes new bearings, fluid..etc + whatever the new posi/gears cost me
or as metioned you can find a 7.5 posi g body rear for 300-400 bux and just swap the whole deal, that can be done by pretty much anyone..setting up a new set of gears is something i leave to a pro.

 

[mysons80elcamino]

thanks to everyone for the information,

I do have the tools to do pull bearings and press them back in at my disposal but im leaning much more towards the rear swap.

so I guess now im looking for a 7.5 with 3.08 gears, could everyone please let me know if they run across one.

Thanks again.......

 

[mysons80elcamino]

so I just found a rear on craigslist for 125$ says its complete everything

not to mention its 7.5 and 3.08 gears, the only downfall is its not a posi rear

can I take my posi out and swap into it? easily?

 

[darbysan]

You can probably swap in your posi ( if the axles have the same splines). Swapping the posi requires some very precise measurements to prevent whine ( backlash setting). It can be done, but it is something I usually leave to a professional. Last time I had gears swapped, even the Pro had to do them over.