Ok.....when I rebuild my T5 Im gonna go ahead and go from a 3.08 rear to 3.73 limited slip. Ive got the 10 bolt rear. The guy told me it would give me an excellent improvement off the line and really wouldnt hurt my mpg. I forgot to ask him if it would hurt my interstate cruising, since I usaully drive around 80 or so and I think the tranny has a .63 OD. I mean I dont want to be running at 3500 rpms and killing my motor. The package price he gave me is an eaton 3.73 ring gear & pinion, limited slip diff, and complete bearing overhaul kit. They want $625. Is that a pretty good price? Thanks!!

 

Lets break it down
Gears (lets say Richmond) $180 for 3.73 for 3 series carrier
Complete rear end rebuild kit (Ratech) $120

That leaves 325 bucks for the price of the posi unit. I say you just buy the SLP take off posi for 85 bucks and use the rest of the money that you saved for the installation cost. The take off posi should be about to handle alot of hp seeing that it was originally on an LS1 z28 or TA that have 310 HP stock.

 

ok....im not driveline literate so I need to know if I need to change carriers for what I want to do. I hve no idea what carrier I have.
All I can say is that its a 10 bolt rear and a 90 model camaro and I want to do the switch above. So is this gonna be a simple bolt in? Or am I gonna have to go through hell?? Please no hell!!

 

I think you got a good price on the parts. Also it won't be too bad on the highway. I just parted out a 87 GTA that had a 305 5 speed, and it had 345s from the factory. So I don't think 373s would be too much of a differance. I turn 2200 to 2300 at 70 in my car with 373s.

 

What RPM's are safe on your engine for freeway driving? I have the TH350 Trans all decked out for racing, im almost ready to drop in some 3.73's.. my car is not a daily driver , mostly city driving and light to light racing.. but if I wanted to go on the highway, what RPM's are safe, and what are border line to hurting the engine?

Nate

 

As long as your not at or close to the redline, you won't hurt the engine any. Back before overdrive, people had 3.73's(and deeper). 3.73's with OD will be fine on the interstate. Actual rpm will depend on what size tires you have. That price seems about right, with some type of gaurantee. I would also have them install axle bearings and seals while it is apart.

http://www.f-body.org/gears/

 

I've had 3.73's since new. 136,000 miles later I still get 21 MPG. The RPMs are 2600 at 70 MPH. I'd say you are safe with the gears.

Consider this: I have a Honda VTR250 that cruises on the freeway at 8000 RPM, all day. It's a thirten year old machine and has never had to be cracked open except to adjust the valve lash.

The only thing that will suffer at the higher RPMs is the gas mileage, as long as your oil film stays intact on the cylinder liner. Keep your oil changed.

 

I have an auto an in O/D with the 3.73's I'm at about 2300rpm at 60-65 but then again I don't have a lock-up converter anymore so it should be a bit better with the stick.

As far as a TH350 with 3.73's my neighbor has an 81 Z-28 with that setup. I don't know about his converter, I think it's stock, but at 55 he's just about 3,000 rpm. Crusing at 70 for any time period on a stock engine is basically out of the question unless you don't care about gas mileage and wearing the engine out quicker.

 

L69 5-speed cars, like mine, came with 3.73s. The cars I had before that, namely older Z28s, came with Turbo 350 or 4-speed (no overdrive in either) and 3.73s.

You'll be just fine.

3.73 gears will not go on your carrier, unless you either use a spacer (that's the next best option behind getting a 3-series carrier) or using the thick gear (yuck - limits your options for the future, but works fine in the meantime).

 

I hsve 3.73 and a th-350 i cruise right along at 60 mph taching at 3000. It won't hurt anthing except gas mileage, actually carrying lower rpm's the engine has to do more work.

 

Since you guys are on the topic - what was being said about 3.73s in a 10-bolt Camaro rear-end? I've got a sport coupe with a posi-10 bolt with 2.73s and i really want to get rid of the gears - go for something 3.42-3.73ish. Would that be wise?

TP

 

YES . If your planning mods on the engine go for the 373s. If your staying stock go with the 342s.

 

This may defeat the purpose, but if you want better cruising and gas mileage add taller wheels on the drive axle, instead of 16's go with 17 or 18's, but of course this will slightly reduce acceleration, since the wheels themselves can be considered another gear.

 

Ive got a stock rear end in my car, and I have the cash, I just dont know what to do to get 3.73 posi in my car... its the stock rear end out of my 82 Z, 2.78 Open rear.. I want to take that rear end to 3.73 posi, what can I do? I cannot change axle tubings, the axle that is there has to stay, because it is welded to my lift bars.... so What products would I need to convert my current rear end into a 3.73 posi rear? let me know what to buy, and from where please.. thank you

Nate