The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Racing and high performance (trucks haulin more than hay)

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 10-06-2010, 06:50 PM   #1
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
12 bolt strength and feasibility:

i understand that the 73-80 (81?) 1/2 tons all came with a 12 bolt. (?)

How much power can these withstand in stock form?


1) Assume 13" slicks, 4.56 gear and a spool.

Would the 4.56 make a difference in terms of strength as in more power would be transmitted thru the rear with the 4.56, so would this stress the rear diff more?
C-10 simplex is offline   Reply With Quote
Old 10-06-2010, 08:27 PM   #2
kpeztruck
Registered User
 
kpeztruck's Avatar
 
Join Date: Sep 2010
Location: Canton, GA
Posts: 229
Re: 12 bolt strength and feasibility:

Quote:
Originally Posted by C-10 simplex View Post
i understand that the 73-80 (81?) 1/2 tons all came with a 12 bolt. (?)

How much power can these withstand in stock form?


1) Assume 13" slicks, 4.56 gear and a spool.

Would the 4.56 make a difference in terms of strength as in more power would be transmitted thru the rear with the 4.56, so would this stress the rear diff more?
I know a couple of guys in the Chattanooga TN area that ran 10 bolts for years in 69-70 model Novas. Both cars ran in the 5.50 range without problems. They had very good (expensive) axle shafts, and spool. Welded the axle tubes to the center all the way around, and ran for years. I run an Chris Alsoton's chromoly FAB9 in mine, with 35 spline Moser axles and center section, but my luck will not let me get away with the stuff I described above. So, I chose to spend the money once. Keep in mind, it took me 3 1/2 years to build my truck when business was still good! Paul
kpeztruck is offline   Reply With Quote
Old 10-06-2010, 11:34 PM   #3
Captainfab
60-66 Nut

 
Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,252
Re: 12 bolt strength and feasibility:

You could likely get away with a 12 bolt, but not with anything stock in the housing. Aftermarket axles are going to be a must. You'll want either C-clip eliminators or weld on new ends for the pressed on wheel bearings (you don't have to use the ends with the Ford backing plate bolt pattern) Then a good quality set of gears.
__________________
Power Steering Box Adapter Plates For Sale HERE
Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE
Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE
Hydroboost Mounting Plates HERE
Captainfab is offline   Reply With Quote
Old 10-07-2010, 09:36 AM   #4
nxtruck
Registered User
 
nxtruck's Avatar
 
Join Date: Jun 2006
Location: Jackson, Mo.
Posts: 607
Re: 12 bolt strength and feasibility:

Quote:
Originally Posted by Captainfab View Post
You could likely get away with a 12 bolt, but not with anything stock in the housing. Aftermarket axles are going to be a must. You'll want either C-clip eliminators or weld on new ends for the pressed on wheel bearings (you don't have to use the ends with the Ford backing plate bolt pattern) Then a good quality set of gears.
X2 on all of this. I would add an aftermarket cover and weld the axle tubes to the centersection, also.
__________________
Chris
1966 Chevy C10 LWB, 434 sbc, TH350, 12-bolt, factory suspension, pump gas
7.02 @ 95.8, 1.45 60'
1965 Chevy C10 LWB, 355 sbc, TH350, daily driver
nxtruck is offline   Reply With Quote
Old 10-07-2010, 01:45 PM   #5
RatPwrd72
Registered User
 
RatPwrd72's Avatar
 
Join Date: Jan 2005
Location: Maysville, OK
Posts: 227
Re: 12 bolt strength and feasibility:

My truck has had a 12 bolt in it since 1982. We're running a car 12 bolt with Mark Williams spool, 35 spline axles and Richmond Pro gears. It has been narrowed with the axle tubes welded. The 12 bolt can be beefed up to handle almost anything, just don't throw a bunch of horsepower to stock carrier and axles.
__________________
1972 Chevy Cheyenne Super- Pump gas 496,TH-400, TCI Stall, 3.73's,Ochre & White two-tone w/Olive
Interior

1967 Chevy Short Step Drag Truck-Iron Headed 468 Making Memories

My momma took me off the bottle years ago.....
RatPwrd72 is offline   Reply With Quote
Old 10-07-2010, 05:11 PM   #6
C20-67_N_MO
Champagne Taste on Beer Budget
 
C20-67_N_MO's Avatar
 
Join Date: Dec 2008
Location: High Ridge, Missouri
Posts: 2,190
Re: 12 bolt strength and feasibility:

Good information here.

So C-clip eliminators sounds like a must have along with better axles as well.

Will be watching this thread to learn more!
__________________
Coming Soon: Project 1970 Country Truck
C20-67_N_MO is offline   Reply With Quote
Old 10-07-2010, 07:55 PM   #7
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
Re: 12 bolt strength and feasibility:

1) Would the stock 12 bolt hold up under 300-350hp/ 350-400tq?
a) Assume 13" slicks, 4.56 diff gear.

b) i'm thinking 300-350hp is good enough for my immediate goals descrbed below:


The reason i'm asking about the rear is because i think i want to go racing and want to start with the rear axle first, then move up the drivetrain with the engine last.

The cars i'm intersted in are 78-87 g bodys( "small" monte carlo/malibu etc.) 73-77 a body---monte carlo/chevelle etc. However, i've been noticing alot of 73-80's pickups going for cheap---well under $1000. i figured since these trucks already came with a 12 bolt, this might be a very cheap way to get started in racing for the short term----all i would need to do is bolt on some slicks, change gears and the chassis is basically done---for my immediate goals which is to run mid 13's.

The disadvantage of the cars i'm looking into is that the rear axle assembelys would most likely need to be changed. And while there are companies, such as Moser, which supply complete bolt in 12 bolts for these cars we are looking at time and around $2000. (this is not including the cost of the car itself).

However, these cars may have the advantage in the longer term---namely weight---maybe 800-1000lbs lighter. Also, i feel that the factory 4-link system is probably better than leafs for drag racing. Especially truck leafs. So, in the long term, if i want to go 12, then 11 etc. i'm thinking it might end up being much cheaper with the cars. Also, with the truck having the leaf springs i'm not sure at what level i would have to add ladder bars or some other traction device.

Last edited by C-10 simplex; 10-07-2010 at 07:56 PM.
C-10 simplex is offline   Reply With Quote
Old 10-07-2010, 11:23 PM   #8
Captainfab
60-66 Nut

 
Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,252
Re: 12 bolt strength and feasibility:

On street tires, a stock 12 bolt at those power levels would be fine as long as it's in good condition to begin with. But throwing 13" slicks on there......I don't know about that. Someone else may have another opinion on that.
__________________
Power Steering Box Adapter Plates For Sale HERE
Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE
Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE
Hydroboost Mounting Plates HERE
Captainfab is offline   Reply With Quote
Old 10-07-2010, 11:35 PM   #9
72lb4x4
Account Suspended
 
Join Date: Jul 2006
Location: DFW
Posts: 1,427
Re: 12 bolt strength and feasibility:

I may not understand things right, since I've just read posts about it but I think the car 12 bolt and the truck 12 bolt are different animals. The truck 12 bolt is supposedly not very good.

In cars, or at least Camaros, the 12 bolt was last used in 1970. 71 and up used a 10 bolt with an 8.5" ring gear making it something between the old 8.2" 10 bolt and 8.75" 12 bolt.

As stated above, I may be full of crap...
72lb4x4 is offline   Reply With Quote
Old 10-08-2010, 02:14 AM   #10
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
Re: 12 bolt strength and feasibility:

Well, that's another possiblity---alot of novas, as kpeztruck pointed out, and camaros came with the 8.5 10 bolt, which i think is pretty strong in it's own right. So this may be another avenue to take as far as getting started cheaply, easily, and quickly. The only thing is that novas and camaros have leaf springs and i honestly don't know how far i'll get before i run into traction problems.
C-10 simplex is offline   Reply With Quote
Old 10-08-2010, 09:59 AM   #11
nxtruck
Registered User
 
nxtruck's Avatar
 
Join Date: Jun 2006
Location: Jackson, Mo.
Posts: 607
Re: 12 bolt strength and feasibility:

Quote:
Originally Posted by 72lb4x4 View Post
I may not understand things right, since I've just read posts about it but I think the car 12 bolt and the truck 12 bolt are different animals. The truck 12 bolt is supposedly not very good.

In cars, or at least Camaros, the 12 bolt was last used in 1970. 71 and up used a 10 bolt with an 8.5" ring gear making it something between the old 8.2" 10 bolt and 8.75" 12 bolt.

As stated above, I may be full of crap...
I don't think that there's a whole lot of difference in strength between a car and a truck 12-bolt. The car version uses a slightly larger pinion stem diameter than the truck version, but that's really the only difference, spec-wise. There's a lot of aftermarket parts available for both units and they can both be built to handle a lot of power.
BTW, the 8.5" 10-bolts are good units, also.
__________________
Chris
1966 Chevy C10 LWB, 434 sbc, TH350, 12-bolt, factory suspension, pump gas
7.02 @ 95.8, 1.45 60'
1965 Chevy C10 LWB, 355 sbc, TH350, daily driver
nxtruck is offline   Reply With Quote
Old 10-08-2010, 03:36 PM   #12
Marv D
Registered Truck Offender
 
Marv D's Avatar
 
Join Date: May 2008
Location: hells training ground (aka Ariz)
Posts: 3,118
Re: 12 bolt strength and feasibility:

I thought the axles and bearings were smaller with the truck version of the 12bolt? If your upgrading axles, c-clip eliminators for bigger bearings, and a spool,,,, weld the tubes and you should be golden. I WOULD invest in a yoke so you could put a decent driveshaft and 1350 u-joints in it. Think of the stock little 1310 U-joints like a 'fusible link' in the drive train. They are really REALLY not up to hard launches on slicks.


And NX,, with ya 1000% there. We run my buddys 74 Nova with a 8.5" 10bolt. Moser axles, Richmond street gears and Strange spool. Welded the tubes and added a big Moser cast aluminum cover with the cap supports. He's been footbraking to 10.2's @ 136 for 3 years now with no hint of an issue. 10.5's are MUCH stronger (with mild mods) than people give them credit for.
__________________
Still playin with trucks, even at my age!

When you're dead, it's only a problem for the people around you, because you don't know you're dead.
.....It's kinda the same when your STUPID.


I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

Last edited by Marv D; 10-08-2010 at 03:40 PM.
Marv D is offline   Reply With Quote
Old 10-08-2010, 10:56 PM   #13
nxtruck
Registered User
 
nxtruck's Avatar
 
Join Date: Jun 2006
Location: Jackson, Mo.
Posts: 607
Re: 12 bolt strength and feasibility:

Marv,
I could be wrong about the axle and bearing sizes between the car and truck hsgs., but, for some reason, I'm thinking that they're the same size.
I know this; either version of the 12-bolt, when properly equipped, will take some abuse, even in these heavy trucks. And I know what you're sayin' about the 10-bolts. I've seen plenty of early Camaros and Novas at the track running them and putting quite a bit of power through them with no issues.
__________________
Chris
1966 Chevy C10 LWB, 434 sbc, TH350, 12-bolt, factory suspension, pump gas
7.02 @ 95.8, 1.45 60'
1965 Chevy C10 LWB, 355 sbc, TH350, daily driver

Last edited by nxtruck; 10-08-2010 at 10:57 PM.
nxtruck is offline   Reply With Quote
Old 10-08-2010, 11:03 PM   #14
KQQL IT
At the body shop.
 
KQQL IT's Avatar
 
Join Date: Aug 2009
Location: Land of fruits and nuts.
Posts: 5,256
Re: 12 bolt strength and feasibility:

Quote:
Originally Posted by nxtruck View Post
Marv,
I could be wrong about the axle and bearing sizes between the car and truck hsgs., but, for some reason, I'm thinking that they're the same size.
I know this; either version of the 12-bolt, when properly equipped, will take some abuse, even in these heavy trucks. And I know what you're sayin' about the 10-bolts. I've seen plenty of early Camaros and Novas at the track running them and putting quite a bit of power through them with no issues.
My friend has a 69 camaro sbc 4spd 8.5 10 bolt in it been 10.60s.
Scares me every time it leaves
__________________
" That didnt make it any newer "
" Dont antique the equipment "
KQQL IT is offline   Reply With Quote
Old 10-08-2010, 11:57 PM   #15
SSedan64
Registered User
 
SSedan64's Avatar
 
Join Date: Oct 2008
Location: Macon, GA.
Posts: 89
Re: 12 bolt strength and feasibility:

Where did the Info about 73-80 or 81 all have 12-Bolts come from?
My 80 1/2-Ton Silverado has an 8.5" 10-Bolt.
From Randy's Ring&Rinion:
79-2001 came with 8.5" 10-Bolt, 92up have 30spline.
63-81 came with 12-Bolt.
73-2009 3/4 & 1T came with 14-Bolt
SSedan64 is offline   Reply With Quote
Old 10-09-2010, 07:48 AM   #16
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
Re: 12 bolt strength and feasibility:

1) i will double check, but i think all 73-79 or 80 or 81 1/2 tons came with the 12 bolt.


2) About these novas and camaros you guys speak of; Are they running the stock leaf spring setup?
C-10 simplex is offline   Reply With Quote
Old 10-09-2010, 12:34 PM   #17
nxtruck
Registered User
 
nxtruck's Avatar
 
Join Date: Jun 2006
Location: Jackson, Mo.
Posts: 607
Re: 12 bolt strength and feasibility:

Quote:
Originally Posted by C-10 simplex View Post
1) i will double check, but i think all 73-79 or 80 or 81 1/2 tons came with the 12 bolt.


2) About these novas and camaros you guys speak of; Are they running the stock leaf spring setup?
For the most part, yes, with the addition of some sort of traction bar ( slapper bars, Cal-Tracs, etc.) and some tuning.
__________________
Chris
1966 Chevy C10 LWB, 434 sbc, TH350, 12-bolt, factory suspension, pump gas
7.02 @ 95.8, 1.45 60'
1965 Chevy C10 LWB, 355 sbc, TH350, daily driver
nxtruck is offline   Reply With Quote
Old 10-09-2010, 10:29 PM   #18
Marv D
Registered Truck Offender
 
Marv D's Avatar
 
Join Date: May 2008
Location: hells training ground (aka Ariz)
Posts: 3,118
Re: 12 bolt strength and feasibility:

Yup, my buddy Dana is running a mono-leaf, calTracks, Rancho shocks and a 9" slick. He is footbraking which is a lot easier on things than a transbrake, But......

http://www.small-block-chevy.com/dana1.JPG
__________________
Still playin with trucks, even at my age!

When you're dead, it's only a problem for the people around you, because you don't know you're dead.
.....It's kinda the same when your STUPID.


I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.
Marv D is offline   Reply With Quote
Old 10-10-2010, 08:30 PM   #19
69trk
Registered User
 
69trk's Avatar
 
Join Date: Oct 2006
Location: bridgecreek ok.
Posts: 1,214
Re: 12 bolt strength and feasibility:

I have a truck 12-bolt with moser 33spline axles, c-clip eliminators, full spool and a billet 1350 yoke for a car 12 bolt that i bought from moser. The yoke, moser told me wouldn't work on a truck, but this one fits and works perfect? I plan on spraying on this rearend, just waiting for some funds for the cage
__________________
http://67-72chevytrucks.com/vboard/s...d.php?t=494388

431 big block times, changed to a 6.0 ls with turbo
1.58- 60'
7.18- 1/8th mile@95.18
11.37- 1/4 @115.81
69trk is offline   Reply With Quote
Old 10-11-2010, 12:23 AM   #20
gchemist
BAD BOW-Silverado XST
 
gchemist's Avatar
 
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
Re: 12 bolt strength and feasibility:

Hot Rod mag compared a 12 bolt vs 9". Each had it's own winning points. Over all, the 12 bolt one due to price and easy of fixing!
__________________
Gerardo a.k.a. Mad Chemist
Silverado XST videos
gchemist is offline   Reply With Quote
Old 10-12-2010, 02:25 PM   #21
Wasted Income
Boosted Member
 
Wasted Income's Avatar
 
Join Date: May 2002
Location: Mackinaw, IL
Posts: 2,200
Re: 12 bolt strength and feasibility:

The Grand National 8.5 10 bolts are strooong...lots of those guys going 9s off the T-brake.

I am running a bone stock 12 bolt with the exception of an Auburn ECTED (electric locker) and a Yukon Gear set. Stock c-clip axles, stock housing, stock rear cover, stock pinion yoke, etc.

Mine has been holding up to a pretty good amount of power (500+ rwhp) on 275 M/T drag radials for a couple years now. Zero issues. My driveshaft was the weak point before the 12-bolt. Emperical data...take it for what it's worth.
__________________
1972 2wd K/5 Blazer Turbocharged 370 LSx - 941 rwhp / 1093 rwtq
1969 Chevy K-10 L33 5.3 / 4L80E / NP241 / 4" lift
1964 Buick Skylark Twin TURBO 383 LS pro-touring project
2014 VW Passat TDI - Daily Driver
Turbo diesel
2015 Sierra Denali HD Duramax Turbo diesel
2023 Ford Explorer ST - Twin Turbskis
2023 Ford F150 RCSB - Whipple Supercharged
2017 Polaris RZR Turbo
2014 Nor-Tech Center Console - Twin Supercharged Outboards

TURBO ALL THE THINGS!!
Wasted Income is offline   Reply With Quote
Old 10-20-2010, 06:04 PM   #22
gearys 5600
Registered User
 
gearys 5600's Avatar
 
Join Date: Mar 2010
Location: tulsa,ok
Posts: 1,085
Re: 12 bolt strength and feasibility:

A good friend of mine ran a 72 swb truck for 5 years at the track almost every weekend on a stock 12 bolt housing,eaton unit,richmond gears,c-clip elim,moser axles..Never a problem.

The truck ran consistent low 10 sec qtr times.
__________________
MY BUILD THREAD http://67-72chevytrucks.com/vboard/s...d.php?t=423629


1969 custom/10 swb--SOLD
1968 swb 50th anniv.--SOLD
1967 camaro ss/rs..LS-6-speed, 16-year long project
1956 chevy nomad
1955 chevy 210 2-dr sedan
1978 el-camino ss 1-owner
gearys 5600 is offline   Reply With Quote
Old 10-21-2010, 12:42 AM   #23
dbmx66
Registered User
 
Join Date: Aug 2009
Location: PA
Posts: 883
Re: 12 bolt strength and feasibility:

we fully welded the tube into the center section, gussetted the ladder bar and coil over backets, 33 spling moser hi-tourqe axels. full spool, moser c-clip elimns and moser 5/8 drive racing studs.

i think ill be fine for strength wise. prolly if you do something similar, i dont know what ur doing suspension wise, but you should be fine.

and btw theres a doorslammer down at the track, he runs 6.50s in the 1/4, its a full tube chassis, glass bodied car, with an f3 procharged 555 bbc on alcohol... and believe it or not, its has 12 bolt rear in it. something broke early in the season (not the rear), and i havent seen him since but..

if hes running one, and is making well over 2000hp i think you should be fine.
dbmx66 is offline   Reply With Quote
Old 10-30-2010, 08:07 PM   #24
Alex1
Registered User
 
Alex1's Avatar
 
Join Date: Jul 2007
Location: Ottawa Ontario Canada
Posts: 1,156
Re: 12 bolt strength and feasibility:

The issue is the pinion shaft! It's quite small in diameter.
Alex1 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:57 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com