T/A1988

So I've been told that gears are the best bang for the buck. I have the good 'ol credit card in hand and I'm ready to buy some 3.73's tonight!!! I have 2.73's now. Is it going to be a big difference? Is this the part I'm looking for? GM: 10-bolt, 7 1/2 in., 7.625 in., 3.73 ratio, 2 series carrier, ring and pinion?

Thanks guys.

T/A1988

By the way, Richmond okay? I can't seem to find any other brands. Oh yeah, my car is a 1988 Trans Am 350 TPI. Thanks.

89BlwnRs

Yes that's right. Those are the parameters you're looking for and I think it'll be Richmond part# 49-0007-1. That's for 3.73s for a Chevy 10 bolt 7.5"/7.625" for a 3.08 and lower carrier (2-series).

Richmond makes some of the best gears in the industry, but they do tend to whine a little due to the angle at which the teeth are cut. This cut is stronger than quieter cuts. You can also purchase genuine GM gears, and I believe Strange Engineering makes gears too. Keep in mind you'll have to change the speedometer drive gear to get a correct reading on the odometer and speedometer.

Hope this helped, any question please ask,

Jason

TransamGTA350

iTrader: (2)

check your rear end before you order. 350TPI's came with the 9-bolt Borg Warner rear. Just get under there and count the bolts on the cover. If it is the BW, you'll have to find gears elsewhere. I'm sure someone knows where to get them, but I know they are expensive.
Borg Warner 9-bolt ratios:
2.77:1
3.27:1
3.45:1
3.70:1

For a relatively stock 350TPI, a 3.45:1 ratio would probably work best. With the peak power at a very low RPM, there would probably be very little or no difference in E.T's from 3.45's to 3.70's. The car will be nicer to drive and get better gas milage with 3.45's. I fyou put on a high flow TPI setup and headers, then 3.70's may benefit you. Hope this helps

89 Transam GTA, a few bolt ons

Pete92TA

I have heard that the GM's dont wine, I have heard the strange do wine a little similar to the richmond. Problem with GM is you have to get a 3-series carrier, which makes it a little more pricey. I am going to do the same thing next year.

------------------
http://sites.netscape.net/bulldogfrazier/homepage
+
http://www.fracoinc.com/


Keep your ride shinning with pride

Scott86Bird

I just did the same thing with my 2.73's in a 10-bolt. Get a posi carrier. 3.73's in an open rear would be a waste. Man, I can spin the tires by just looking at the gas pedal.

If you have a 9-bolt I'd probably find a nice complete 10-bolt posi rear with 3.08 or higher numerically and put that in the car. Then look for the gears.

Scott

Hank Brote

I just installed a Strange 12 bolt into mine and the grears are a quiet as anything. In fact I expected a little whine but there is nothing.

------------------
Hank
87'IROC Z28
http://personal.atl.bellsouth.net/atl/b/r/brote/main.htm

MikeDwhoROCZImports

iTrader: (1)

I've got an 87 IROC that originally had the open rear-end with 3.23 gears. I then found a cheap 89TA Posi-disc rear end with 3.27 gears and swapped that in. I broke a tooth on the pinion (God know's how, I've got an LG4......wonder why I got the rear so cheap?), so I was forced to buy a new ring and pinion. The cheapest one I could find was from Strange Engineering, and with the installation kit, cost me well over $400!!!
Having no prior experience with rear-ends, I bought a video and read up on some information from Richmond gear on how to install rear-ends. I put the rear-end together 4 times (checking backlash, adding shims on eather side to get it centered at the right point) before I got the correct backlash and wear pattern (tested with some white paint gunk type stuff) on the ring.

I put it together and now it whine's loudly (espically under acceleration) from 40-50mph (on the speedo, probably 35 actually) and is not noticable after that...until you drive by a cement barrier on the highway and can hear it echo back at you.

Is this normal, or do I have to take the damn thing apart AGAIN and check to make sure its all in the right position???

MikeDwhoROCZImports

iTrader: (1)

And a word of advise.....if you have a 9 bolt Borg Warner like I do, find a 10 bolt, ANY 10 bolt, and build that up instead. Gears are WAY to expensive on the 9-bolt and the rear-end is only rated at about 300hp...

Birmass

I want to do the same thing with my 2.73's, but I haven't had ANY luck finding a posi around here. They are like gold. I'm not to knowlegdable on this, but can I use my rear end and just change the internals to make it a posi? I would go to 3.73's.

------------------
88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

Kevin91Z

iTrader: (1)

Yah, you need a 3-series posi for 26 spline axles, and the gears. Jegs sells the posi for $305, last I saw. It might be worth while to get a complete 4th gen rear end.

Oh, and I traded my 3.42 10-bolt for a 3.45 9-bolt, for strength.

spud

Scogin Dickey sell ring gear spacers, You can use series 3 gears on a series 2 carrier.
Mine worked perfectly. The good part is them only cost $45.


------------------
82 Firebird,355,Cam 224/234, .466/.488,TH350 Tranny,650 HolleyDP,Hooker Headers(I.E. POS) Manual steering,Lakewood LCA's,15X9 Centerline Warriors 275 50R15's BFG Drag Radials
Best 8th et 8.81@80mph.

Birmass

Thanks.

------------------
88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

vortecfcar

If you go with a newer 28 spline posi carrier, like in a 4th gen, you'll need custom axels, I ordered mine from dutchman engineering in oregon for about 240 with shipping (good price).

------------------
91 RS W/carbed 350, Vortec heads, performer rpm, Comp cams Xtreme energy 268 grind. BFG Drag radials. 3.42 posi,Corvette servoed 700r4, ****ty stock converter
13.24@104

Eric91Z

What about those of us that already have a 28 spline axle? Don't the '91 Z28's have a 28 spline? If that is correct, can't we use the take out 3 series carriers from SLP and then add the new gears?

I was planning on using this "new" posi unit from SLP with Motive 3.73 gears in my '91 that currently has the factory 3.08 gears and a posi unit that is getting weak.

Speaking of which, does anyone know the correct speedo and driven gears to correct the speedo for the new rear gears?

Thanks.

------------------
Eric Mann
esmann@quixnet.net
1991 Camaro Z28 305/M5

Kevin91Z

iTrader: (1)

Eric, yes you're correct. 28 spline axles found in 90-92 thirdgens can use the same posi units made for 4th gens. But I dont know which speedo gears to use.