Need some input on what I NEED to suit my purpose.
I have a 99 FRC, stock rear end 3:42's, would like to go to a 3:73.
I'm lost on the "1 rib", "2 rib" hardened shafts etc. Will only be pushing 475 HP maybe....
Can someone give me a lesson on this, please.
Can't see the hardened shafts for 450-500HP. Has to be overkill, had a 475 HP 72 LT1 that I slalomed and never needed anything over sock even with sticky tires.......

TIA

 

If you are running 475rwhp and plan on doing any racing with sticky tires you will probably blow up the diff sooner or later. Personally that would be the main reason for upgrading the diff - going from 3.42 to 3.73 will not really be noticeable. If you just want gears go at least 3.90, 4.10 even better. That's a change you will notice, and you can upgrade to hardened parts at the same time. Paying all that labor to just swap the gears is a big risk because if you grenade the rear you can be looking at an entire new diff and possibly transmission. Big expense for not spending the extra money while the diff is apart.

Dope

 

Here,,, Check this out. I did the the C6 ZO6 hardened output shafts, DTE spyder gear cross shaft, and new C6 clutches with improved belview springs:


- C5, Its Go Time, Output Shaft Install - Left and Right : http://forums.corvetteforum.com/c5-t...post1573404441

- C5 RAGTOPWS6, Differential UP-Grade; http://forums.corvetteforum.com/c5-g...-z06-guts.html


Dont mess with the pinion support UNLESS,,, you have the Kent Moore Tool

Hope this helps.

BC

 

Hi Bill.... should have known you'd already "been there, done that"!
How are ya?
Still a little confused on a couple of points....
1..How do they differentiate between 1 rib 3 rib? Is that the 3 rib on the left side of one of your pics?
2..Don't think I have to "upgrade" the diff yet. Still working good, no use fixin' something that ain't broke, yet, right?
3... But if I have too, what is the parts list I will need to upgrade the diff without changing the gears?
4... Is there more parts needed if I DO change the gears, of course over and above the gear set? Any recommendations on manuf for the gear set and ratio above stock?


THX
Bruce

 

I would upgrade the shafts! i broke my left shaft with a 3500 launch at the track with only 430rwhp...

 

C5 Differentials and Components


We offer options to upgrade your diff, or built units that are ready to plug and play. The "1 rib" was used up to 01, "3 rib" would be 01 and later. This is refering to the ribs that run along the top of the diff from the trans flange back. If you have a 99 and no one has ever changed it, you have a 1 rib. If you purchased a diff from us and requested a 3 rib, we would have to adjust the core charge. It is always better to replace the diff before it blows so that you would recieve the most out of your core. Frankly, I would recommend hardened shafts at your power level and up. This is one of those situations where "while your in there" you may as well get it over with so it isn't a question mark in your car.

 

Bruce

Nothing was really wrong with my rear other than I knew that I had a broken Belleview spring on the passenger’s side. (I could tell due to the differences in the burn out marks )

I’m at the 450 RWHP level and I believe that an ounce of prevention is worth a LOT more than a POUND of cure. Once it POPs, your bank account will NOT be happy.

So, During my clutch replacement, I broke open the rear-end and replaced the limited slip clutches and output shafts.

If you read those two posts, ALL of the part numbers and things that you will need are outlined and accurate. You can also contact Gene CULLEY www.gmpartshouse.com and tell him you need ALL the software for a rear-end rebuild (plus any hardware that you determine necessary) and he will assemble you a package. MAKE SURE that you tell him that you want a differential to transmission O ring also.

Installing both the C6 ZO6 output shafts, seems like a very logical and effective up-grade at my power level. As you can see in the linked post, there redesigned and improved.


I also ordered a tranny/differential BRACE and will be installing that.

Unless you have the special KENT MOORE Differential alignment tool, the proper shims and the required training to set up the rearend, DO NOT try to do a gear swap your self. Find someone or a specialized shop to do the job! Your real end will most likely FAIL in short order. Doing the short and long shafts, clutches, BV Springs and seals, does NOT/should not effect gear alignment.

I had George at Rockland transmission up-grade my spare MN-12trans to a TRANSZILLA T-60/60 tranny with all the up-graded bullet proof parts. The hardened main output shaft is another insurance step.



Bill

 

Bruce, you should post what you are going to do with your FRC. If you are into drag racing, yes, do all the upgrades listed on my thread. Those C6 Z06 output shafts have withstood 930 RWHP/830 RWHP cars that are drag raced (both traps high 140 MPH).

If you are just Auto X'ing, you don't need any of the upgrades IMHO.

Bill is correct on the gears. Leave it to someone who has experience with them.

 

Listen to this cat. He knows his stuff. I call him Master Kim due to his transmission and differential building ability, not his Tae Kwon Do skills.

And for the record, I'm the his one of his 900+rwhp test pilots. Working on taking it to the 1krwhp mark before I hit the track again with my stock C6Z diff and RagtopWS6 built trans.

 

Thanks Bret, I know you are one of the innovators who figures out what you need and accomplishes that goal. The RWHP is a side effect rather than something to brag about. I know I WILL see that 9 sec/150 MPH next year!

Sorry to side track.

 

Exactly what I did to mine a 2 months ago. Still doing great.