i have an 89 L98 that has the crappy 2.77 rear end that sucks and wanted to know if there are any replacement gears that i can swap in instead of buying a new axle. if not what kind of axle should i get to replace this one. im really looking for somewhere in the ballpark of 3.73-4.11. i rode in a 305 that had 4.10s and that thing would snap your neck way harder than my 350 with the crappy 2.77s

 

Best you can put in the 9-bolt rears is 3.70 gears, and you'd have to buy gears and a new carrier.

Buy a 10-bolt, you'll save a ton of money. It's not worth it to spend over $1000 to convert your 9-bolt to 3.70s, when a 10-bolt with 4.10s would cost much less.

 

I also have those wonderful freeway gears and I've called around a little about replacing those 2.77's.. most of the people either refer me to another company or just flat out laugh at me about the availability. The common theme is to find a 10 bolt replacement. I own a 99 with mild bolt on mods and it's on the second set of gears. The 10 bolt isn't as strong (so they say) as the 9 bolt, and if you're running 350hp+ (at the rear wheels) I wouldn't recommend it. The best setup (but as normal, the most expensive)is installing a 12 bolt if you're running some serious power.

 

I had 2.77 and switched to 3.70. It was a big differnce and now I'm switching back but I think I have the gears and posi sold. stick with the 9 bolt. after you buy a disk brake 10 bolt and buy a posi and gears you will be way over what you spent for the 9 bolt stuff. these guys that think you are better of with a 10 bolt are crazy. The vast majority of the people on the board have mid 13 sec and higher cars and they arn't going to be braking a 9 bolt unless they do something dumb.

------------------
89 Formula 350
Rebuilt suspension, Aluminum Driveshaft, 3.70 gears
Best 1/4 mile - 15.08 bone stock.

 

Jeffro89formula350, I hope that comment wasn't directed at me. I've got both the 10-bolt and a 9-bolt I was going to put in my Camaro. The aftermarket plain sucks for the 9-bolt, but the 9-bolt IS a nicer axle than a 10-bolt from the factory.

It WILL cost less to get a used 10-bolt and buy the gears he wants. I know two people who searched high and low for cheap carriers and gears for the 9-bolt axles, and it was going to cost well over $1000 to convert one guy's 2.77 rear to 3.70s.

How much did you spend on your switchover, Jeffro89formula350, out of curiosity? Maybe I haven't looked where you shop for parts, and haven't seen the decent prices you've seen? I dunno... Help me out here!

There are just more parts and differential options for 10-bolt axles. Yes, they're design makes them weaker than the 9-bolt, but at least they have an affordable aftermarket.

 

You are right in that they are not easier to find.. and that comment was not directed toward you but it seems in these cases everyone always says go with the 10 bolt. I spent a total of $700 on my parts for my conversion. I picked up a used carrier although very low mileage and bought a set of 3.70 gears for around $350. With posi, rebuild kit and gears Plus install i was under $1000. I'm building a 69 camaro now with a six speed and stuff so I'm done working on my formula....

------------------
89 Formula 350
Rebuilt suspension, Aluminum Driveshaft, 3.70 gears
Best 1/4 mile - 15.08 bone stock.