Data plate # on 8.8 IRS diff

bermblaster41 · #1 (**permalink**) 11-17-2006, 06:51 AM

I have hurricane motorsports cobra with an 8.8 IRS diff. Trying to find out what gear ratio I have. The data plate reads S513B 3L08882L17. Any help would be great. Bermblaster!

mj_duell · #2 (**permalink**) 11-17-2006, 07:28 AM

If you are sure of the first 4 characters in this code (3L08882L17)

3L08

Then you have a

3.08 Ring Gear
"L" designates Limited Slip.

--Mike / Turn Ten Racing, Inc.

bermblaster41 · #3 (**permalink**) 11-17-2006, 07:42 AM

thanks Mike. What is the difference between limited slip and posi track? Thanks again. Bermblaster

bermblaster41 · #4 (**permalink**) 11-17-2006, 07:46 AM

I just checked it is 3L08. Is that to high of gears? I have a tremac 3550 with .68 5th gear Thank Bermblaster

mj_duell · #5 (**permalink**) 11-17-2006, 07:51 AM

The "Limited Slip" would be the Ford Traction-Loc diff. "Posi" is actually a GM designation that gets used by everyone else, but is essentially the same thing. 3.08 is high, but will give you great drivability and mileage. If you are looking for a good performance gearing, I would look between 3.55 and 4.10. This would depend on your needs.

--Mike / Turn Ten Racing, Inc.

bermblaster41 · #6 (**permalink**) 11-17-2006, 08:08 AM

The cobra will never see a track. I am using a stroked 351 to 408. Just want good performance. Back tires 315/35 ZR17. Just want the soil factor

[pasenger side] on the onramp accelleration. Not to concerned about off line performance. Thanks again Bermblaster

mj_duell · #7 (**permalink**) 11-17-2006, 08:18 AM

Quote:

Originally Posted by bermblaster41

The cobra will never see a track. I am using a stroked 351 to 408. Just want good performance. Back tires 315/35 ZR17. Just want the soil factor

[pasenger side] on the onramp accelleration. Not to concerned about off line performance. Thanks again Bermblaster

Of course you do! I would look at a 3.55 or 3.73 and I think you will be happy. Keep in mind if you plan on really wailing this diff you should get things like a Ford Racing 8.8 Rear End Girdle or a hardened gear set.

--Mike / Turn Ten Racing, Inc.

bermblaster41 · #8 (**permalink**) 11-17-2006, 08:29 AM

Thanks Mike for your time. Had the car since June and things have finally slowed down to where I can dig in. Thanks again. Bermblaster

undy · #9 (**permalink**) 11-17-2006, 10:25 AM

Given the Tremec 3550's 3.28 first gear I'd consider your 3.08 diff ratio ideal. I had a Richmond 6 speed in a 69 Stingray. The 6 speed had a 3.28 first gear also and Richmond Gear tech said the 3.08 would be the prefered gear for street/strip duty. I went with the 3.08 as recommended and it was perfect. I've got 3.73s in my Cobra now and used to have a 3550 with my old engine combo. First gear was vitually worthless on the street. The TKO600 is better with it's taller first gear.

Dave

bermblaster41 · #10 (**permalink**) 11-17-2006, 10:30 AM

thanks Dave. That makes me feel better. Time to dig in. Bermblaster