Chevy 10 bolt

[chpseat987]

I have a 72 Nova I just baught on this site and the guy said the rear end is a Chevy 10 bolt 4:56 built. Thats all I have, I have not opened it up yet but my Chevy truck 1989 has a 10 bolt under it and looking at the 2, the one under my car the pumpkin is twice as big as the one under my truck. Is there different 10 bolts how do I find info on the one I have I am scared my new 550 to 600 Hp 427 is going to rip it out from under the car. Are there casting numbers? or any way I can dertermin just what i have

[TopspeedLowet]

If you are not embellishing on your power #s you should remove the tinker toy piece for something more substantial for the long term. 10 bolt means almost nothing but how many bolts hold the ring gear on the carrier. It could be a GM 8.5" gear set like the grand national and older pickups used to use or it could be a trans plant and has a 7.5/8" ring and pinion. the low power chevelles used a variation of this set up 8.2" as well. you will need to remove the cover which by bolt pattern alone will tell you most of what you need to know. your parts store usually has a picture of the gasket surface for each which is an easy way to tell if it is 8.5 of 7.625 job. the 8.5 I have used with some luck with 500 HP on it but requires frequent checking to be sure you don't destroy it. Your axles will be toy 28 spline if you have 7.625 car. some Tahoes used 30 spline but both are stock wimpy pieces so spooling should not be concidered ever. I hope this helps you get started.

[chpseat987]

Wow ok so ill remove the cover and see if there are 10 bolts holding the ring gear on the carrier would i be able to measure the ring gear as well to determin what it is?

[TopspeedLowet]

The size is part of the gear set # often clearly stating. If you have an aftermarket gear set it will be noted on the ring gear. If the cover is smooth it is likely a 7.625 if it has a bump out for the ring gear like a 12 bolt it is likely a 8.5. When you see the carrier bearing caps, you will be on board with what I mentioned about TOY piece.

[us7race]

You can sometimes get lucky and it may still have the stock pinion nut which would be 1 1/4 if it is a 8.5
But if it is a 1 1/16 it is an 8.20

[chpseat987]

After a couple friends looked at the rear end it does have scars on the ring gear but they are richmand after market gears so the rear enf has been upgraded, even though it still is a 10 bolt, I dont have alot of money to fix or upgrade because of what the engine is costing me, So I am going to run it until it goes, but I noticed that there is a re-in forced cover for sale with bolts that touch the main caps with only about 10 pounds of tourque on them for 150 bucks, If I was to get one of these covers would it help or would I be wasting my money, hopefully the rear end will make it this season and next winter I can save some money and I want to back Half the car with ford 9 and make a big tire car. :?

[TopspeedLowet]

After a couple friends looked at the rear end it does have scars on the ring gear but they are richmand after market gears so the rear enf has been upgraded, even though it still is a 10 bolt, I dont have alot of money to fix or upgrade because of what the engine is costing me, So I am going to run it until it goes, but I noticed that there is a re-in forced cover for sale with bolts that touch the main caps with only about 10 pounds of tourque on them for 150 bucks, If I was to get one of these covers would it help or would I be wasting my money, hopefully the rear end will make it this season and next winter I can save some money and I want to back Half the car with ford 9 and make a big tire car. :?

You are going the right direction. I ran that with billet caps with studs and that is about all you can do to strenghten a GM piece. you will be ok without the billet caps. That is just all one can do to prevent the carier from being ejected out the rear.

[us7race]

With my 8.5 10-bolt (stock caps and cover) I have only broken 1 set of gears and that was right at the end of this past season.
My 60' are 1.32-1.36 at 2865lbs. I wouldn't be worried at this time. JMO.

[TopspeedLowet]

With my 8.5 10-bolt (stock caps and cover) I have only broken 1 set of gears and that was right at the end of this past season.
My 60' are 1.32-1.36 at 2865lbs. I wouldn't be worried at this time. JMO.
Nice looking shot! You should advertise for GM powertrain / proving grounds. (':D')

[JEFF69Z28]

CALL MOSER YOU CAN GET A SPOOL 33 SPLINE AXLES AND C-CLIP ELIMINATORS FOR ABOUT 650.00.33 SPLINE AXLES ARE GOOD UP TO 1100 HP THATS WHAT MOSER TOLD ME AND THATS WHAT I GOT FOR MY 8.5 10 BOLT OUT OF A BUICK GN.

[cepx111]

With my 8.5 10-bolt (stock caps and cover) I have only broken 1 set of gears and that was right at the end of this past season.
My 60' are 1.32-1.36 at 2865lbs. I wouldn't be worried at this time. JMO.
It has more to do with weight and torque, what works on a 2500lb vehicle wont last for $hit in a 3800lb vehicle, plus there wasnt a bigblock made from the factory that didnt have the bigger 12 bolt carrier.
My buddies has a 71 nova, 496BBC he's broke countless 8.5 gear sets, and he has the billet caps, studs, aluminum cover, after market axles the whole nine yards. He was finally convinced to upgrade to a 12 bolt after the last set only lasted 3 weekends.
But on the flip side - I have a buddy who has a fully narrowed 8.5 ten bolt in his tube chassis 68 firebird w/ 427 sbc that runs 5.90's all day long w/ short times in the low 1.30's, he's never had a moments trouble out of it, not that I would have done it but its just an example.
I think yours will be fine at your Hp level and weight, when your money gets right > stick a DANA 60 in there and forget about it.
Goodluck, Cp

[Tod74]

You can sometimes get lucky and it may still have the stock pinion nut which would be 1 1/4 if it is a 8.5
But if it is a 1 1/16 it is an 8.20

I just learned somethin'

[chpseat987]

you and me both espically in this forum, Thank you everybody and your comments, I have had a couple people come over and look at it, it has richmond gears and they look heavy duty, there are scars on the spiders and the ring gear but my buddie said the pinion is set real deep into the ring gear, wich is a good thing, the wear we see may be normal racing wear, my pocket book wont support anything else right now so I am just going to clean eveything up real nice, use a good synthetic with the proper additive ( any suggestions there) and run it till it breaks, if it even does break, in the future I want to back half the car and run drag tires 15 or 16 wide, so until my pocket book can afford that I will run with my fingers crossed for this season. I am running on the car MT street drag radials and with the clutch pack in the rear end I am hoping that those 2 in combination will take exseive stress off of the gears.

[cepx111]

You'll be fine don't sweat it, the last thing you need is to be worried about breaking something when your concentrating on a race, if it breaks so what, you can fix it.
You'll need some of that nasty smelling friction modifier stuff from the dealership, the stuff at autozone will not work.
It's about $10 for a 8oz bottle at the dealership and you'll need at least 2 to do the trick also use a name brand synthetic oil > costal or walmart brand lube won't cut it.
Goodluck Cp