Since I've seen this topic lately I thought I would share what I know. Unfortunetly I think the mag is at work so I'll check tomarrow. Some others must have seen this mag article too.

I have heard (read) that the high powered early years had a different drive line than the emissioned later years. The later years just didn't need the heavier systems since the engines were enemic and the goals were different for the engineers.

The article I have to find mentioned that the SBs had a smaller drive shaft and half shafts than the BBs. Also the side yokes.
The SBs also used u-bolts to attach the u-joints where the BB used bolts.
In a catalog I see listed 2 half shafts,'63-79=3" diameter. '64-79 = 2.5" diameter. So maybe the later models don't have a difference from the early SBs

Its been mentioned that the U-joints will break first then the shafts (in these comparisions) well on my BB with 4:11 , close ratio and high revving BB ( I didn't get the engine) my left rear spindle broke. I feel the original owner had something to do with the spindle breaking. If you were to get this package I think it likely to be popping the clutch regularly. I don't know if any of the other componants were ever replaced. So for me it wasn't any of the parts being discussed that broke.

A 'Vette can't handle a lot of power?
Consider what they were being built for and who was designing them. Also consider that if the drive shaft or half shaft was to come free then this becomes a very dangerous componant. My spindle broke in a parking lot while slamming the brakes on to avoid an accident, the spindle broke internaly to the housing so it is still contained, probably by chance.
But this is a relative term of whether it can take HP. How much is alot and what are you doing with it?

I think that The 'Vette not able to handle HP is in reference to the later models. Since no cars built during this era had any HP it would be true to say that none of them, made by any company, can handle HP over what they were using at the time.
There is a distiction between the BB, SB and later emission- trying to survive years.
There was a factory available engine that produced 600+ hp with a stock factory rear end. This was meant for racers who were expected to race the car so it was packaged for this. If the rear end couldn't handle this much power then the name Corvette would have been given a terriible blow on the race track.
Also if these componants were breaking then the accident it resulted in would have hit the news and courts.


The Corvette is really built to be a road racer not a drag racer. If someone wants to race you they generally back off when you throw some turns into the race. There are alot of compromises such as the half shaft/independant suspension that wouldn't really be needed for drags. Conversly if you take a 'Vette that has been turned into a dragster it no longer will perform on turns, Small front tires and all that.

I would be interested to know if any one who has increased their HP substantially has suffered any drive line problems. And if they did anything to the drive line. Also if they actually stress the componants.
Another words any real life experience.
I've only read what I have said above, except for my spindle, and would be interested in any other opinions.

 

I've had a variety of engines in my Corvette, all the way from the unimpressive stock 200hp Crossfire motor, a 450hp Superram 383, the 650hp naturally aspirated SBC427. I drove the car hard for 2 years with the 383, and this past fall with the SBC 427.

The only thing I have done, besides switching out the 700R4 for the TKO, is to replace the driveshaft when I did the tranny swap to one using 1350 ujoints, Tom's Differential forged rear spindles and solid ujoints all the way around. I rebuilt the diff about 4 years ago - new clutches, metals, bearings, etc, but kept the original carrier, spiders, crosspin, etc.

I think the key to it's survival has been the fact that I have kept street tires, although road race G-Forces, and have been careful about sanely launching it. The majority of your failures are going to occur at launch in 1st gear since that is when the driveline is loaded the most and being exposed to the most torque, due to the torque multiplication of first gear.

I am seriously considering getting the 30 spline yoke/spindle/half shaft setup with 1350 ujoints from Tom's while I wait to get the turbo system fabricated. That seems to be the strongest setup available if you want to keep the stock-type IRS.

 

Hey Monty, what is a 1350 u-joint? I've seen references to that in a few places, but never understood it.

Clueless in NJ...



[Modified by Flareside, 3:09 PM 12/16/2001]

 

Techo, I can think of two members that broke their drivelines in the last few weeks, Gordonm and 427Hotrod. Hopefully, they'll pick up on this thread.

-Joe

 

I pulled the ring gear off the carrier but it was a 4.11 with a spacer. (A NO NO) I found out the hard way. I think a good set of ujoints and inspect the rest of the parts for wear and you should be OK. As Monty said with slicks the breakage point goes up. Shock is the biggest problem. They used to launch L88 cars with slicks and survive. Unless you are running 500 lbs of torque with slicks you should be OK. There is always the possibilty of parts to break

 

1350 ujoints are the largest size automotive joints. There are also 1310 (smallest) and 1330 ujoints.

 

Monty,

I have seen alot of information regaurding driveline endurance vs increased horsepower. However I have only heard comparisons of launching hard with street tires vs slicks. It appears that because slicks hook up much better you run the risk of driveline failure due to the increased load on the drivetrain at launch. How would you compare Z rated tires as opposed to R rated tires or even slicks.

Although I am not a drag racer, I will occassionally visit the track with friends for some fun. I just upgraded to Z rated tires. How much better will these hook up than R rated tires and what is the potential risk if any vs the R or slicks to my drivetrain.

Hope you can make heads or tails out of my question. Thanks in advance. :seeya


[Modified by ScubaJKD, 2:44 PM 12/16/2001]

 

I'm like you, I don't consdier myself a drag racer (and my reaction times show it ;)), but I like to go a couple times a year for fun. I have borrowed slicks on a couple of occasions and my 60' time dropped accordingly compared to when I was running G-force raod race style tires. However, I haver run better times with the G-forces than I have with a regular all-season type street tire. Obviously, there is probably no surprise to any of that but I think it does illustrate that the softer compound of the road-race style tires do get better traction than street tires, but not nearly as much as a drag radial or slick.

The G-forces were Z rated and the rear end held up fine, but that was with my 450hp/480 tq 383. I never ran the car with the 427 in it with the Z rated tires, so I can't say for sure if the combination of the increased torque and the somewhat stickier Z tires would be enough to break something. Just a guess, based on my '60 time, but I think even with the lower output 383 but with slicks, the there was more load. Once the tires start spinning, the applied load to the driveline parts is reduced, even as engine torque increases.

 

I recall reading somewhere that the vette rear (63-79) is good for 750 hp. Tom's differentials sells a 12 bolt version that is considered near unbreakable.

The most likely point of breakage would be the half shaft u joints. I would make sure that they are always in good condition and use the best parts (Spicer for one). The driveline shop where I bought mine guaranteed that I would twist my half shafts before I broke the U joints.

The next weakest point would be the stock manual transmission (Muncie). There is a reason that Lakewood sells adaptors from GM engines to Ford and Chrysler transmissions. The muncies were more designed for road racing then drag racing. The gear helix angle on the m-22 doesn't make it stronger than the M-21. It just reduces the thrust load on the gearbox which reduces temperatures in a road racing application.

To be a serious drag racer (slicks) in a 63-82 vette you would need to upgrade most of the drive train from the engine back. NHRA rules requires a six link rear suspension under 11 seconds (I believe) and a cage for under 12 seconds. As mentioned before a vette is more designed for road racing.

 

Thanks for the info Monty, that helps me to put it into perspective. I just finished building my 383 I hope I can get even remotely close to the performance out of it that you got out of your 383. Best wishes. :seeya

 

74vetteman,
I disagree with your statement about the strength of a M-22 vs. M-21 the gears of a M-22 are made of 9310 nickle and the M-21 out of 8620 which is not as strong. The reduced helix angle also makes the gears stronger, look at a Jerico or a Rolltec, maybe even a G-force (all pure straight cut 9310 gears).The M-22 is the strongest trans of those used in the earlier Vettes. And if it wasn`t worth $1900. (when i sold mine), it would of been used in my racer looong before the super T-10`s which are now gone replaced with a "rolltec"
...redvetracr

 

Yes, the m-22 has a higher nickel alloy gear which is better at absorbing impact loads, and the 20 degree angle of the gear submits less thrust loading on the gear box.

However, the m-21 has a 45 degree angle which creates a longer gear (so to speak) which has more area to support the load.

I disagree that the reduced helix angle makes the gears stronger. It does reduce the thrust load on the case and bearings which in turn reduces heat generated by the gearbox which is why racing gearboxes use them. Most race boxes use spur gears.

In either case, the capacity of the gears exceeds the capacity of the case. Gear zone now manufactures a heavier duty aluminum case and a nodular iron midplate to reduce case flex.

 

74vettman,
The two pieces you speak of are both designed wrong the case does not allow the front bearing to act as a vent and the midplate has the groove for the snap in the wrong spot. Those pieces are also not made by "gear zone" only sold there. They are made and distributed by Auto gear,who also sells the crap Italian M-22 gears. ...redvetracr

 

I didn't realize there are problems with the case and midplate. I posted on gearzone's web site's bulletin board to see if anyone was using those parts but did not get a response. It's too bad they have problems because the stock Muncie case does require strengthening for high torque, drag race type applications. I also didn't realize the new Italian gears were crap. Can you explain why.

I also thought the owner of gearzone (Paul) was instrumental in designing and getting the parts manufactured. He basically infers that on his website. Sorry to pass on bad info.

I also realize that the m-22 is slightly stronger than the m-21. I only said it isn't the flatter helix angle that does it. It is the higher quality of the gears. Most high speed industrial gearboxes use a 45 degree helix angle because it provides the most tooth area on the gear which makes them stronger. In those applications thrust loads and heat are less of an issue.

 

I may be wrong on this but I believe a straight gear is the strongest, also the noisiest. The longer tooth contact on an angled gear is curving along the diameter of the gear. The curvature of the gear makes the contact patch about the same.

 

I split the carrier this spring. The diff was a total loss. This was at a very sticky drag strip with my Hoosier road race tire.

 

Here's what a ZZ4 can do to new Federal Mogul greasable u-joints. On the positive side, the new parts are looking good! BTW, I now use Brute Force solid u-joints... But I'm with you... To hold a u-joint in your hand and think this is all that's really keeping your shafts together is a tad scary!! This is just some of the damage. You should have seen the battery box!

 

74vettman,
The Italian gears are NOT made from the correct material (9310),they took a proven design (GM) and are now on "their" third redesign series,the bores on the gears are incorrect, too tight i believe. I wish someone(and i have asked paul at gear zone, and did NOT get a straight answer) What is there to design?? They are using the GM designed gears which were perfect, the only problem with the GM stuff is they didn`t make enough of it and it`s almost all gone and also very valuable! The guy who does my stuff rebuilds alot of Muncie and Super T-10`s he has told me the people he knows (in the trans business) who sell the Maestro(sp?) gears will SELL it them,but will not use them. And by the way you can buy a complete gear set all 6 gears for $450 or $495 ,NOT the inflated price paul gets. His web site is there for ONE reason, to sell parts and to sell his video which i have heard is NOT complete.The thickness of the front part of the case does not allow the front bearing to be used as the vent and the mid plate has the snap ring groove in the wrong place. There is, i guess a "fix" for the case but they are giving refunds on the mid plates. ...redvetracr

 

Sorry Techno, you are wrong. This quote is from the Technology of Machine Tools, Second Edition. "Because of the progressive rather than intermittant action of the teeth, helical gears run more smoothly and quietly than spur gears. Since there is more than one tooth in engagement at any one time, helical gears are stronger than spur gears of the same size and pitch. However, special bearings (thrust bearings) are often required to overcome the end thrust loads produced by these gears as they turn."

Anyways, no big deal. Cheers!

 

I don't want to start an argument but the biggest improvement you can make to your rearend is to get rid of the manual tranny and replace all your U-joints with solid joints (non-greasable). Now I'm not anti-manual shifting...infact I prefer the fun of running a car through the gear changes and my first two corvettes were 4 speeds. But when your dropping 500 plus HP thru the drive train and running slicks an automatic is much easier on all componants than a stick (besides being deadly consistent). I'm strictly into drag racing, the vast majority of the winners and most consistent cars slower than 8 second quarter mile times run automatics.
Now if your into road racing or just street driving for the fun of it...that's a different story...keep your manual tranny...stay away from slicks.
Anyway I've been running the last three years with slicks and am now pushing 500 HP and 500 ft. lbs. torque and have had no driveline failures...my 60 ft. times are 1.60's (I am running the smaller diameter driveline). Deen