My new 355 engine is about ready for me to pick up and soon my stage 3 700R4: what I'm wanting to locate is a set of better gears for my 9-Bolt/2.77 rear-end. I'm unsure which gearing is best for the rally/road coarse usuage with the occasional 1/4 mile:

I think I'm limited to the optional (g92) 3.27 & 3.45 carrier and gears????


My 2.77 posi is in great shape and I've upgraded the entire rear disc brakes. I'm unsure if I should be contacting a local shop/wrecking yard or??? for whatever I'd need to make a switch. The new engine will be pumping out a basic 355-365hp and was put together with an emphasis on torque. I'll have to dyno it before it get's installed.

Does anyone have any suggestions of what is the best route for me to take to find a fairly quick solution?????
I'd appreciate ANY knowledgeable hints! Nitro

 

For rally / road course usage I'd say ditch the auto but I'm biased.

3.70 ratio is available with a 9bolt as well but the aftermarket is non-existant.

 

http://www.reiderracing.com/gm734.htm

3.73 gears for 9-bolt, I believe they were around $250 when I priced them. ended up finding a set of 3.70's and used them instead


the problem for you is going to be your 2-series rear, you'll have to use a set of stock gears and won't be able to go above 3.27 gears without swapping to a 3-series carrier.

 

I could use a little education on this issue; Isn't the 'carrier' the whole casing for the rear gears and axle housings? If I went to a wrecking yard, how would I differentiate between a third/2-series 9-bolt rear?

I don't need deep 4.xx gears for the quarter mile, but do want lay a bit of rubber when I'm pulling onto the freeway! I suppose I'll need to go to a rear-end shop to find out how to work the formula to figure out what gears my new 360hp/360(ish) torque and a 700R4 will benifit best from for all around driving...
Are there actual heavy duty gears available for our 9-bolts (versus the factory units)

 

the carrier is the posi unit, the part the ring gear bolts to. I don't know how to tell the difference between a 2 and 3 series carrier. other than the stock gear ratio. usually 3.08 and down is gonna be a 2 series, 3.23 and up is gonna be a 3 series

 

I have the 9 bolt with 3.27 gears in my IROC. I have 263,000 miles on my IROC and still have not had to rebuild the rear end or the 700R4 trans.
I personally would not go lower gears than 3.27s. TPI units work better at lower rpms having no problems to pull hard from 2500 to 5500 rpms even in 3rd gear. I have a little more HP than you but I'm still running the stock TPI plenum and tubes.
just my 2 cents.

 

I have what you need...

Set of low milage(less than 60K) 3.27's and posi-carrier, was going to put them in a rearend I bought from TRaviZ, but never got around to it.

Anyway, you can have the posi-carrier and gear set for 150, I'm about a 2 hour drive from you.

If you want, I could install them and set them up in the rear I got from TraviZ, for another 150...you'd just have to put your brakes on them and stuff it under your car...the housing I got from TraviZ didn't have the brake hardware on it.

 

Traviz sure has given a lot of us great deals on parts; I've bought a couple things from him. I"m absolutely interested, although it's just after midnight and I'm headed for bed. We'll definitely talk. I did just completely redo my rear brake system but would have to probably pull it to replace the rear axle seals to do it all correctly. Let me think about it more in the morning when the alcohol wears off.......! Nitro