Are ring gear spacers as evil as every "salesperson" makes them out to be ? I really,really need a new set,my 2.56 rear end is no fun at all!I think 3.73's and a powertrax locker are definitely in order,however I'm on a budget so any suggestions would be great!My car is a 71 with a lovely 8.2 open diff. It's my daily driver as well.Thanks!

I changed from a 10 bolt to a 12 bolt in my 70 chevelle. The 10 bolt had 2.73 gears and and open diff. I moved to a 12 bolt which has 4.10 gears and a posi. I have heard that powertrax makes a good product, however it does produce some noise while turning in the corners. but if I was you I would almost go with a 3.55 or 3.30 gear ratio. This way in case you have to drive on the interstate you are not cursing yourself. I run 60 miles per hour @ 3300 rpms. I am sure 3.73 will not decrease it much more than 3000 rpms @ 60mph. I would go with something a little higher geared unless you plan to buy another car. You will like the posi it gives you a lot of traction especially if all you do now is spin one tire.

P.S. I do have another car and I plan to change the gears to a 3.73 or 3.55

Ben Matheny
1970_Cloned
TCG 214

one more thing I have a 3 series carrier and I use a spacer to bolt on the 4.10 gears and unless you are planning on putting slicks on your car don't worry about the spacer. I still plan to use a 700R4 even with the 3.73 gears to lower my RPM.

1970_Cloned

I changed from a 10 bolt to a 12 bolt in my 70 chevelle. The 10 bolt had 2.73 gears and and open diff. I moved to a 12 bolt which has 4.10 gears and a posi. I have heard that powertrax makes a good product, however it does produce some noise while turning in the corners. but if I was you I would almost go with a 3.55 or 3.30 gear ratio. This way in case you have to drive on the interstate you are not cursing yourself. I run 60 miles per hour @ 3300 rpms. I am sure 3.73 will not decrease it much more than 3000 rpms @ 60mph. I would go with something a little higher geared unless you plan to buy another car. You will like the posi it gives you a lot of traction especially if all you do now is spin one tire.

P.S. I do have another car and I plan to change the gears to a 3.73 or 3.55

Ben Matheny
1970_Cloned
TCG 214

Make sure you use a good strength bolt such as grade 8

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According to what I've read in the magazines - no direct experience here - a spacer carries almost none of the load and the bolts do all the work. In a performance situation it may not hold up. I'd get the correct carrier and eliminate a potential source of later aggravation.

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members.tripod.com/dfdolerjr

sean
there right the bolts do carry most of the load,but the bolts carry a load without the spacer,the reason for not using a spacer is that when one is installed, the bolts are out of the threads more than without,let me put it this way. It is easyer to bend or break off a nail if it is sticking out an inch, moreso than it is if it is only sticking out 1/4 of an inch,understand?ring gear spacers have a tendency to break there bolts due to the added torque they must withstand. my advice, get the right carrier for your gears. well,hope this helps 67rat member #199

The bolts don't carry much of the "shear" load but rather it is clamping force that does the holding. It is when clamping force is not suffecent that bolts shear. Toqure them down to specification and go like hell 500-600HP easy. 10-12 grade 8 bolts is a lot of PSI holding (clamping force) strengh.I could look it up for you but belive me its many thousands of PSI.
Harley

actually because of the relative scarcity of gm posi units for swapping I believe richmond makes some gearsets with extra thick ring gears so no spacer is necessary, but depends on the application. I think they were only for 12 bolt rears..

Richmond makes them for 10 bolt also. I have a 4.56 set to fit a 2 series carrier.

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Philip Valentine
Team Chevelle Member #42 GOLD
philip@chevelles.com

After working in a driveline shop and seeing both of these different things, the spacers and the "cheater gears", I would have to recommend the "cheater gears" above the spacer. With these, you use the stock bolts. The spacer requires a longer bolt, which is more prone to shear than a shorter bolt.

The best recommendation tho, is to do it right, once, by purchasing the correct carrier, the correct gearset, and the correct bearing kit, and having it done correctly at a reputable driveline shop. Every time we put in "cheater" gears, they usually end up back after a short while getting redone, out of warranty, BTW, because warranties do not cover gear breakage. Gear breakage is considered abuse and most gear manufacturers will not cover it.

Also, the biggest problem with spacers is getting a proper setup and tooth pattern. They are very hard to set up, so we won't even touch them at my shop.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103

o.k. I will let the cat out of the bag,I use a ring gear spacer on my 67 427 ss with 4.88s, what i read about these spacers was all negitive, but I never had a problem.Iwould go with the richmond (thick) ring gear set up,harley,your right, If good grade 8 bolts clamp It tight enough,It should take some hefty horsepower, I just posted what i read about them,ya know in the mags. welp,good day dudes! 67rat member #199

oops, sorry, see next post!

[This message has been edited by Scooter (edited 08-05-99).]

Posting what you read is ok, but I'm speaking from experience on this one. Both the spacers and the "cheater gears" are not nearly as strong or reliable as the correct carrier with the correct gear. You may save a couple bucks up front with either the spacer or "cheater gears" but in the long run, you are money ahead by doing it right. I've seen it enough times to warrant this advise, but it is up to you people to listen and decide what is best for you.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103



[This message has been edited by Scooter (edited 08-05-99).]

Don't do it!!! They are sloppy at best. The ring bolts are the only thing keeping it together. By design, the ring gear should ride on the "shoulder" of the carrier. The bolt holes in the ring gear are close tolerance and the ones in the spacer are to big. I wouldn't do it under any circumstances.

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I suppose that Cardiac has it right. The problem with ring gear spacer si that they no longer locate the gear on the "pilot" diameter of the differential case. However, the testimony given here seems to suggest that they have had no problems. This the classic case of science competing with technology. I once worked for a company that made rear axles (Dana) and their engineering guys would gasp if you mentioned a spacer. That was 30+ years ago and the spacers still work. So, I think if you assemble an axle with a spacer, check the gear contact pattern every 90 degrees and make sure that the bolts are super-tight.

My experience with a spacer was not good. The first time I sheared off all the bolts (the ones that came with the spacer)it was just inconvenient, the second time I was going much faster and the broken bolts made a nice drain hole of about 2" diameter in the bottom of the case.

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Philip Valentine
Team Chevelle Member #42 GOLD
philip@chevelles.com

well,
heres my thing,488s,ring gear spacer,427.-----------no problem.thats from exp.I guess im lucky, or could it be the gears are set up right,who knows. the right carrier is the best way to go! 67rat member #199

[This message has been edited by 67RAT (edited 08-06-99).]

My Chevelle had 4.10s with a spacer on the original 3 series posi. It broke at the track a few years ago, BUT I can't say it was because of the spacer. I lost 3 ring gear teeth, each about 120 degrees away from the other. (I keep wondering if it was from 3 different launches or did 1 tooth take out the others.) I didn't find out about it until I pulled into my garage after driving home from the track (70 miles) and saw a nice trail of gear lube running up the driveway and ending in a puddle on the garage floor under the rear. One tooth got caught between the cover and the gear about a mile from my house (I followed the trail), and poked a nice hole in it. I'd had the car at least 10 years by that time and had subjected the rear to MUCH abuse. If I had to, I'd use a spacer again without hesitation.

[This message has been edited by Larry (edited 08-08-99).]

Thanks so much to everyone for your responses.I got alot to think about!I've been in the hospital for the last week and now I'm home for a two month recovery from back surgery.It really made my day to see all the great help from everyone.