rear end gears

[snk1994]

Im thinking I want to swap out the rear end gears in my vette for a more aggressive gear. Dont want to go 4-11's or anything but it just seams to me that the factory gears were really intended for freeway crusing instead of street performance. Anyone have any sugestions or advice? what I should first look at? pricing questions? Will the rear gears out of a 72 vette work in the 81? Just brain storming right now so any comments would be greatly appreciated.
~Steve

 

[81 Corvette]

the carrier that is in there can hold up to 3.73

I went with 3.54 and its one of the best mods one can do. If you do any highway driving, 3.73 will be too much imo unless you toss in an OD tranny. I think the 3.33 range isn't a big enough jump for the effort.

I don't think the 72 gears will fit.

 

[LannyL81]

Yeah, I agree....the 2.73 is great for the highway (well from what I remember of actually driving my L81 1.5 years ago!!!). I have been wanting to swap out that gear set too, but figure while I have the diff out (again) I think that I should do the wheel bearings. Then I added up the costs for everything.....OUCH!!! That's hitting $1500!!

Check-out Randy's Ring and Pinion web site for gear prices as well as just doing a complete swap of the diff (most expensive way though). They have the complete range of sets available.

Ahhh now this has got me thinking I should just do it and do it right!!! Its only money right....can't take it with you right?? May be if I sold a kidney......hmmmm.

Later,
LannyL81
Tucson, AZ

 

[snk1994]

I must be getting over. Everyone I have talked to is saying $1,500. There is a great place up here in Washington state called Corvette and High performance. I talked to them and they were telling me $1,500 for a complete new rear end with gears and they do the work! I would rather buy the gears and do it myself but that is looking like a great price from what everyone else is telling me.

Just called randy's. They are great on the phone. He gave me some Gear ratio options and did soome calculations with the new gear ratios and tire size so I would know what RPM i would be turning on the freeway. Im leaning towards the 3.73's. The best part is that they are $303. That covers gears and installation kit with all the seals. I think this will be about the best performance upgrade I can make for the money. Will get alot more off the line power then I have now. I wont have that supercar 150MPH speed but I never do that anyway.

Now the next thing is that I have never done this before. Chad at randy's says its a pretty easy job as long as you follow the exact procedures. he said that 99% of the time when people mess it up it is because they figure "close enough" on some of the steps and you have to be pretty accurate. can anyone give me a little insight on what Im getting myself into? I dont want a torn apart diff laying in my drive way and my car sitting outside up on jack stands for days while I wait on friends to come over and help.

And damn never thought of that Kidney idea....think your on to something......


~Steve

 

[dfw81shark]

I must be getting over. Everyone I have talked to is saying $1,500. There is a great place up here in Washington state called Corvette and High performance. I talked to them and they were telling me $1,500 for a complete new rear end with gears and they do the work! I would rather buy the gears and do it myself but that is looking like a great price from what everyone else is telling me.

Just called randy's. They are great on the phone. He gave me some Gear ratio options and did soome calculations with the new gear ratios and tire size so I would know what RPM i would be turning on the freeway. Im leaning towards the 3.73's. The best part is that they are $303. That covers gears and installation kit with all the seals. I think this will be about the best performance upgrade I can make for the money. Will get alot more off the line power then I have now. I wont have that supercar 150MPH speed but I never do that anyway.

Now the next thing is that I have never done this before. Chad at randy's says its a pretty easy job as long as you follow the exact procedures. he said that 99% of the time when people mess it up it is because they figure "close enough" on some of the steps and you have to be pretty accurate. can anyone give me a little insight on what Im getting myself into? I dont want a torn apart diff laying in my drive way and my car sitting outside up on jack stands for days while I wait on friends to come over and help.

And damn never thought of that Kidney idea....think your on to something......


~Steve

My 3.54's are slightly annoying on the highway. I'd hate to imagine 3.73.
The 3.54 gear with about 280hp and the automatic got my car to 60 in a hair over 6 seconds. Plenty of wheelspin when necessary too.

You can get a whole unit from Ikerd's for $795 with your choice of ratio. From what I've read, it is the same as Mid-America sells.

http://www.ikerds.com/merchant2/merchant.mv?Screen=PROD&Store_Code=CP&Product_Code=300-000


Before I saw this, I had bought the gear and rebuild kit separately and had it in the shop. My rebuilder hadn't done a Dana44 Corvette (80-82) before and after I got it back he said he'd probably never do another one. It was pretty tricky to get back together with the new ring and pinion. I think I paid $200 for the ring and pinion, $120 for the rebuild kit and $150 for the labor. I pulled it myself. Be sure to get all new bushings for the mount (There are 4 iirc).

http://www.madvet.com/shop?frame=4.303.1434

Part numbers (2) 602-806, (1) 602-810 and (1) 602-812


The 602-806's are a ***** to get out, and need to be pressed back in. Use the search box to see some people's techniques. Mine was a combination of drill to drill out the rubber, dremel, prybar, and sledgehammer. I used a 50ton press to get them back in. I'm sure that was overkill though.

 

[snk1994]

What RPM's you turning at 60MPH? I talked to a sales guy and he said it wouldnt be so bad, but then again he is trying to make a commision. The tires I have on the rear are 295/50/15's. I just dont to put in something and then kick myself later for not going more aggresive....then again I dont want to put in something and kick myself for being too aggresive and not be able to drive it on the freeway.

 

[dfw81shark]

What RPM's you turning at 60MPH? I talked to a sales guy and he said it wouldnt be so bad, but then again he is trying to make a commision. The tires I have on the rear are 295/50/15's. I just dont to put in something and then kick myself later for not going more aggresive....then again I dont want to put in something and kick myself for being too aggresive and not be able to drive it on the freeway.

According to the bowtieoverdrives calculator, I'm doing 2640 at 60. I usually cruise at 70, and that's around 3000rpm. With 3.73's, I'd be running 3250rpm. That doesn't sound like much more on paper, but it will in the car. I was doing the same speed with the old 2.87 at 2400rpm. MAJOR difference. I'm running 255/60/15s. The price of the 3.73 shouldn't be much more- like the same price or within $10 or $20.

If you get the 3.73 and decide it is too tall of a gear, think of it as a good excuse to get an overdrive.

 

[81 Corvette]

here is my file that i used to help decide on what gear to go with. I'ts set up for a stock gear of 2.87 and has comparisons for 3.31 3.54 3.73 and 4.10. You just put in the engine rpm for the 2.87 gear, adn it'll give the engine rpm for each of the other gears and what speed you will be traveling at that rpm.

its a pretty simple little file, but its nice to be able see multiple gears side by side.

enjoy

http://www.domesticmisfits.com/81/gears.xls

 

[GerryLP]

here is my file that i used to help decide on what gear to go with. I'ts set up for a stock gear of 2.87 and has comparisons for 3.31 3.54 3.73 and 4.10. You just put in the engine rpm for the 2.87 gear, adn it'll give the engine rpm for each of the other gears and what speed you will be traveling at that rpm.

its a pretty simple little file, but its nice to be able see multiple gears side by side.

enjoy

http://www.domesticmisfits.com/81/gears.xls

I am very happy with my 3.31:1.

With 270/60 R15's in the rear, an XE274 cam, 9.5 CR (I thought I had 9.7 CR, but I removed the engine recently and veryfied. 9.5 CR :ugh ), and the TH350C with 2,400 stall, the car is lively at 70 MPH. I turn approximately 2,900 - 3000 rpm's at that speed, and even though it is very noticeable at first when compared over the stock 2,200 rpm at cruising speed, I still managed to get approximately 18 miles/gallon on my run to Auburn, IN.

GerryLP:cool

 

[snk1994]

Well looked at that chart. that helps alot. Im still leaning towards the 3.73 just because I dont do alot of open road freeway drivin. Speed limits around here are all at 60MPH anyway and me being younger (31) and driving a red Corvette the cops are already staring at me anyway. Dont want to push the speed limit too much or will be investing in the Police fund instead of the Vette.

Have been putting off any major modifications since Im here in Baghdad, Iraq but going home TOMORROW!:W

So with 3.73's and keeping it at or below 60MPH I should be fine. Really appreciate your insight though. And like you said I can always go with the Overdrive if Im not happy.

 

[dfw81shark]

Well looked at that chart. that helps alot. Im still leaning towards the 3.73 just because I dont do alot of open road freeway drivin. Speed limits around here are all at 60MPH anyway and me being younger (31) and driving a red Corvette the cops are already staring at me anyway. Dont want to push the speed limit too much or will be investing in the Police fund instead of the Vette.

Have been putting off any major modifications since Im here in Baghdad, Iraq but going home TOMORROW!:W

So with 3.73's and keeping it at or below 60MPH I should be fine. Really appreciate your insight though. And like you said I can always go with the Overdrive if Im not happy.

Awesome. Here in Texas it's all freeway.

Congrats on getting to come home, I bet it's a long time comin. I personally couldn't imagine. You guys rule.

Good luck with the 3.73s, how much of work are you going to do yourself?

 

[snk1994]

Just Got Back From Baghdad!

Just got home today. Wow great not to be over there anymore.Im thinking about doing it all myself. I havnt ever torn into a rear end myself but with some determination and the right instruction I know I could do it. Another reason for this first post is to try and get an idea of how difficult it will be. Have access to all the tools so that shouldnt be a problem. On a difficulty scale what do you think this is? Should I just spend the money and have someone else do it? Should I just get a whole rear end with the gears I want and put it in?


~Steve

 

[kingman]

Swap rear ends???????

I have a 96 with the 3.07 so called performance ratio. If l went to the 3.54 which would make the most sense, are you telling me that l can just swap the gears and keep my old ones?

And how much should this cost?

Alan