[joeyj]

I have a 12 bolt in my 67 camaro. How do you tell the difference between the 3-series and the 4 series carrier? I've had the gears changed twice, originally it was a 3.55:1. Then a 4.56:1 and now a 4.11:1. But I dont know if the carrier was ever changed. Now you can get 4 series gears that will work in a 3 series carrier. So I dont know what carrier I have. I am wanting to install a 3.08 for my future 6 speed trans

[70 RS/Z-28]

It's likely still a 3 series carrier given that's the way it came from the factory and you're right you can go up to 4 series gears in a 3 series carrier, but not the other way around.

[Scooter]

If you are going to be adding a 6 speed trans, you may be very disappointed with 3.08 gears. When you hit the overdrive gear, you'll wish you had the 4.56's in there. It will be great for highway and mileage with 3.08, but performance will suffer, big time.

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70 & 1/2 RS
SB406 & M20 4spd
9" rear

70 Malibu 350/TH400

Gold member #103

[Joseph]

I agreee with Scooter. 3.08's are not a good choice with that tranny. Leave the 4.11's in for now and swap your tranny, I think you'll be much happier. With a 1994 or newer t-46 that has a 0.5 6th gear you should be around 2500 rpm @ 75 mph or so I think.

Just my thoughts

Joseph

[Bri]

JoeyJ, Scooter and Joseph are right on the money. You probably won't even be able to use 6th gear with a 3.08 rear and the performance will be poor. In 6th gear, with 0.5 ratio, and a 3.45 rear I was running 2,300 at 75mph. Keep the 4.11!

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Bri

[JOE58]

There should be letters and numbers stamped on the pass. side axle tube. They can be decoded to tell you the original series and ratio for that rear end.

[Doug Garland]

there are #'s cast on the chunk itself.The 3 series is a # 140, the 4 is a #174 I think.I'm sure about the 3 series though.

[joeyj]

Thanks for all the info guys... I am going to install a Richmond 6 speed with a 4.28 1st gear and a .80 6th gear. I am also going to change my rear gear to a 2.73. That will give me 11.68 final for 1st and a 2.18 for 6th. Right now I have a 10.52 final for 1st, so this will give me a LOWER 1st gear than I have now. Also at 65 I will be turning 1853 rpm in 6th gear with my 25.7" tires. In 5th gear (1:1) at 65 I will be at 2321 rpm. And in 4th gear (1.24:1) I will be at 2874 rpm. I think this gives me a fairly wide range at my disposal and my driveshaft, u-joints etc wont be spinning so fast. And two great things about the Richmond are it will bolt in with only a rear crossmember mod (4" back), and I can order it with ANY combos of gears. Tell me what you guys think.

[davidpozzi]

I did a richmond 5 speed for a firend in his 69 camaro. We changed from a 4.10 to a 3.08 rear gear. It turned out he had a 3 series carrier and we removed the spacer ring. We installed new ARP ring gear bolts while we were at it. We basically wound up with the same gearing as the 4.10 in 1st, 2nd, 3rd and 4th, with the 5th gear at 3.08 he runs 2600 at 65 with a 26" tire. We lowered the shifter mount and moved it forward and to the right to come out of the console. The hurst setup is too high and to the rear. We used a turbo 400 crossmember off the origonal frame holes, but you could easily use a four speed crossmember and slide it back.
It's a lot cheaper trans and fits easier too. I don't think you will use the 6 th gear with the 2.73 rear, the engine will be running too slow. Also you will have to change to a 2 series carrier which will cost more. BTW richmond gear makes a 3.08 thin ring gear set that will fit the 4 series carrier.