rear end decisions
 

Got a 69 c10 with an original non posi rear end. Not sure how strong they are. I hear a lot of pros and cons about them. Found a 9" rear housing on CL for $50 and was wondering which housings are stronger, the 9" or the one I got in the truck now?

truck is being built for 95% track usage.

Re: rear end decisions
 

Probably 90% of the guys will say go with the 9". But you will have to dump quite a bit of $$$ into that $50.00, 9" to get it narrowed, setup and under your truck.

Re: rear end decisions
 

Yeah I know it will be a pretty penny to build it up, but won't it cost about the same to do it with the rear end that's under my truck now?

Re: rear end decisions
 

That depends on what you need from that 12 bolt diff. For street only you can stay with the c-clip axles you have. If this a dual use truck for both street and strip then you will need to get rid of the c-clips.
Then comes the big one. Can you do the work yourself and do it correctly or will you need to send it to a diff shop?

If you can cut the ends, replace them with ford ends and new axles you can probably do the entire diff including an upgrade to an Eaton posi carrier for about $900.00. If you have to send that 12 bolt to a diff shop, the cost is going to be nearer to 1500.00 and, for that money, I would either build or buy a nine inch built to the width you need with all of the correct bracketry.
It's a matter of your skills and money. mostly money.:lol:

Re: rear end decisions
 

What kind of power will you be putting to the rear end? What size tire are you planning on running? There are a few guys here that are running the truck 12 bolt, with some respectable times.

Re: rear end decisions
 

The truck will be 95% strip with about 5% street. I'm pretty sure I can have my buddy do all the welding on it and I can do the rest. Depending on rates of local quotes, I guess I'll just have to compare prices compared to buying one already made to meet my needs

Right now the motor has about 650 foot pounds of torque and 525 hp. By the time I actually dish out the money on a rear end, I'm hoping to be close to if not more than 1,000 foot pounds of torque and close to if not more than 900 hp. My goal is to get up to around 1,500 foot pounds of torque and more than 1,000 hp without nitrous in order to stop building up the motor. Size of rear tire I'm planning on running is 33.5" x 17"-16 goodyear eagle slick or a 33.0'' x 22.50'' - 15'' with a 17'' tread width Hoosier quick time d.o.t. drag tire.

Re: rear end decisions
 

I used the 12 bolt that was in mine. Had it narrowed and had ford Torino ends put on. Axles, bearing ends, narrowing all done was about 500.

Re: rear end decisions
 

Your gonna need one serious rear for 1500 pounds of torque. Forget about anything stock and go straight to Mark Williams site and break out the mastercard. Nothin in the stock world is going to tolerate that. I have a 9" with as Strange Pro spool and gear and aluminum centersection under a 2600 pound chassis and 797HP and IMO it's is not far from it's limits.

Williams site has some great info on what you need to keep it safe at various ET's, power and weight.

Re: rear end decisions
 

I agree with Marv D

With those kind of power numbers, a 9" isn't goint to cut it. You're going to have to really step it up to something like one of Mark Williams' own differentials. I don't know if a Dana 80 or a built 10.5" 14 bolt would tollerate that or not.

I would suggest looking thru this thread to see what you are going to need in a rear end.

http://www.67-72chevytrucks.com/vboa...d.php?t=469935

Re: rear end decisions
 

Checked out Mark Williams site at their rear ends. As for choosing gear ratio, not sure about those. And with wheel to wheel dimensions, are they asking inside rim to inside rim or inside tire to inside tire or what?

Now as far as bolt patterns go, you think it might be possible if they could make it 6 lug instead of 5x5 or 5 1/2x5?

Re: rear end decisions
 

I like Alstons site for their tech sheet. It give you a good work sheet to start with.

http://www.cachassisworks.com/Attach...structions.pdf

Re: rear end decisions
 

Im gonna say Dana 60 as a minimum . If you are headed to the power levels posted above , then no need to build the rear end twice or three times . 35 or 40 spline , 10 to 10.5 ring gear , 5/8 studs and as many as possible considering fullsize truck weight and big power . I believe currie has a size calculator that will fill in the blanks .

Re: rear end decisions
 

You can do that with a 9 inch. I wouldn't use a factory one though. Get a Fab 9 or have your friend weld back braces to good tubes. Then a Moser or a Strange center section and you are set.

Chris

Re: rear end decisions
 

Moser Dana 60 w/35spline axles,Spool,4.30 pro gear, Billet 1350 yoke, big bearing Impala weld-on ends. Holding up well with transbrake and low 1.30 60's on a 31x14 Goodyear slick.

Re: rear end decisions
 

Trying to find the Like button for this ^^^^^^

Re: rear end decisions
 

As for your rear end and the ones that others have suggested, what made you go with a Moser Dana 60 and not something else? Also, would a rear end like yours hold up to the power I'm running now (650 ftpnds)? What about 1,000+ ft pnds torque?



Also, lets take a few steps back. As for the power I'm running now, my set up is, 650 ft pnds torque 525 hp, built turbo 400, stock 12 bolt non posi rear end, and 28x12x15 goodyear slicks on 15x10 tims. Trailing arm suspension. Front and rear suspension has not been modified in any way yet.

The information that has been put in this thread is great. Still want to hear more about rear ends and such for the kind of power that I want to make in the future. But, as for what I'm making now, I'd like to also know what would be a good rear end, and what kind of power it can handle.

Would I just be better off buying or building a rear end that can handle the power I want to make in the future, that way I don't have to worry about blowing it out at any point of time?

Re: rear end decisions
 

http://www.moserengineering.com/hous...d-package.html
The Moser Dana 60 package now has an option for 70-72 Chevy trucks brackets if you want a bolt in.

I'm currently at 700tq on motor and + nitrous nearing 1,000tq. I had built the 12bolt truck rear w/33spline moser axles and twisted splines and bent housing tubes twice. And reason for a Dana was it's not a 9" . What motor combo are you running?

Re: rear end decisions
 

I'm still running the original 8.5" ring gear 10 bolt housing under my Chevelle. Been running it for 35 years.

Current set up is 555 cu in big block, around 950 HP naturally aspirated, TH400 (full manual valve body, no brake) and 4.10 gears. MW spool, axles and c clip eliminators, welded tubes.

Best ET is 9.85 at 136 mph, at 3950 lbs. Car has been going 11.80s or faster since 1990.

K

Re: rear end decisions
 

The sterling 10.25 comes to mind also .

Re: rear end decisions
 

A good 9" will do it just fine. Use an aluminum center section with the big pinion support, a pro gear and 40 spline gun drilled axles. Now the big problem is getting the rest of the truck to hold it. With that power level I would put a full chrome moly all round tube chassis under it. 4 link rear with a strut front. You can get away with a really good power glide but I would put a bruno or lenco drive in it. Those power numbers look like blower/turbo numbers with that huge torque or something well over 700 inches.
Jimmy

Re: rear end decisions
 

That axle sounds about right. Do you think it would hold up to more power than what you have?

I may have to look into your rear end as well. Running it for 35 yrs is a long time. Would it hold up to more than 1,000 torque?

10.25?

As far as the chassis goes, I'm planning on something similar to a pro-stock chassis or even a funny car as far as layout goes. I'll defiantly look into the transmissions you listed. Now should I do a 1 piece drive shaft?

As for motor, keeping it under 700 Cubic Inches, but will either be single or twin turbo non-alcoholic.

Re: rear end decisions
 

I'd invest in a posi or spool for your dogleg 12 bolt. Who knows??? It may take it... A 12 bolt is pretty tough

Re: rear end decisions
 

If you look at the rule book you are getting into the very regulated chassis specs. You are also getting into a very high dollar chassis. The last top sportsman car I put together was a tad over 130K out of the owners pocket and that was a used Don Ness car and a new motor and trans. Just tell you chassis builder what power you have and let him handle the suspension and rear end. Don't be shocked at a 40K bill from him for a roller.
Jimmy

Re: rear end decisions
 

I don't know PG,, will a 1000 pounds of torque put him below a 8.50 chassis cert? It for sure depends on it hooking and the power getting through the chassis, suspension and all the way to the track. As you well know, a lot of things between this 1000 pounds of flywheel torque and the track can keep the combination WAY slower than anyone might expect.

Still a 8.50 cert is going to be deep into his pocket. A roller 8.50 car in the 2500ish pound weight is still beckoning $15k $30k+ just depending on the quality / age of the build. And buying a used build is about 30¢ on the dollar these days.

I honestly feel your $'s are very VERY realistic!! Low&slow,, prepare for sticker shoc in what the rest of the package is going to cost!

Re: rear end decisions
 

Well the under 700 inches and a single or duel turbo making up to 1500 but at least a 1000 is 1300 plus HP. With a 706 making about 1300 hp and a 1000 ft pounds at about 2550 lbs with the driver we went 7.19 at 192 in not so good air. A truck wont go through the air like a grand am but if I had that much power like he wants to build and and could not run 7.80s some one is getting fired. A good chassis design and someone who knows what to do with it will be needed and 25.1 car will be what he has to have.
Jimmy

Re: rear end decisions
 

I was thinking that as well just for something now before I start building the motor or even some kind of stock posi ford rear end, but at the same time, I don't want to build a rear end to have it break when I add more power.

Jimmy, I'm much aware of the price tag to do what I want to do. I'm hoping that maybe a sponsor or 3 can help out with the price. I can't imagine those big cars being built and raced without sponsors.

\

I get what you are saying as well. I'm not looking to go any faster than 8's

Jimmy, those are quick times. Since you guys seem to know more about the rules, is it a realistic goal to have and not go any faster than 8's while keeping as much as a stock body as I can without fiberglass?

Also, what's a 25.1 car?

Re: rear end decisions
 

I am working on going 8's.. Right now I have:

A steal front clip but no hood and cut up inner fenders
Stock front suspension but home made cross member
Stock frame from the front to the back of the cab, CM round tube from there back + 4-link
12 point CM cage
Alum Gen 4 motor with power glide
Summit racing seats

With that said, truck weighs 3,200lbs with me in it, full tank of gas and full 15lb N20 bottle.

I am in the middle of swapping out a built 12 bolt for a 9"

Re: rear end decisions
 

SFI Spec 25.1E
Application: Pro Stock-type tube chassis roll cage; 7.49 seconds and faster; 2,800-pound maximum.

All I can say is 1 sponsor for every 1000 sportsman racers. Ya gotta know somebody and then have something pretty 'unusual' that will warrant a 'donation' to the cause. I would venture to guess that most of the cars you see slower than 5 seconds are sponsored by the owner (Or owners business)

Re: rear end decisions
 

Very ambitious....

...but it can be done.

This is my engine builder's car. 477 cu in big block, naturally aspirated. The car has gone 8.20's on motor. The only glass is the front bumper and hood. Built by himself in a one car garage in the Detroit suburbs.

At the events I attend (mostly NMCA Fastest Street Car series) this car is on the high end of well running/stock appearing.

By the way, that #1 on the windshield: that's earned. Four time NMCA World Champion in the Nostalgia Muscle Car/American Muscle categories. I runner up'd twice
in my 15 years with the NMCA/NSCA. Guess who beat me? (lol)

Re: rear end decisions
 

Well going racing in a truck or a car takes a good plan. First is what class, next how fast do i want to go, then what rules do i need to meet to go that fast. About what will it weigh, how much power do I need to go that fast and how do I want to make that power. The more detailed the plan the better the end result will be with only having to do things once.
Jimmy

Re: rear end decisions
 

Look into the 2003 and newer 2500 series GM vans. They have a D60 axle that has 3.5" axle tubes and huge bearings. With some custom shafts, it would be a stout setup.

Re: rear end decisions
 

Going low 8's on that tire is quite an accomplishment!!! What is it a 8.5" slick?

Re: rear end decisions
 

26x9 M/T slick, or he sometimes runs a drag radial.

I tease him that my front tires are bigger than that.

He actually got thrown out of a Milan All Motor meet because his tires were too small....at least that was the excuse they used. ;)

K

Re: rear end decisions
 

what???

Re: rear end decisions
 

I'm not kidding. There were a lot of words over that one.

It's a beautiful car which was built to the letter of the rules. I guess some folks were pretty desparate to find something wrong (after getting themselves embarrassed by its performance).

K

Re: rear end decisions
 

Your 12 bolt will take 650 Ft-Lbs without too much stress but it will never stand up to 1500. You will need a bullet-proof professionally built diff for that.

Re: rear end decisions
 

Alright. That's good to know just till the end of the summer. As for the 12 bolt, should I build it up a bit with a posi in it to handle the nos I may run or find something else just for now? Either way, I need to get a posi.

Re: rear end decisions
 

Thank you sir , this is great information , learned something today .

8's on a 26 x 9 is getting it done.

What is your fastest pass so far without a posi unit ? were you planning on spraying it with an open diff ?

Re: rear end decisions
 

I agree. Great info here.

[/QUOTE]What is your fastest pass so far without a posi unit ? were you planning on spraying it with an open diff ?[/QUOTE]

R/T: .078
60': 1.972
1/8: 8.443
MPH: 83.02
1/4: 13.053
MPH: 100.56

I'm not exactly sure what my rear end is. I can do a burnout and the passenger tire spins, but I can do another burnout in a different location and the driver side tire spins. I know it's not a posi though. I've had a posi.

Re: rear end decisions
 

Tech keeps the poor guy slow unless he keeps clear of the track... Ridiculous prices! I could build a nice house and prolly do it in less time.... What's the deal there? Gut check! That's why I bought a welder. And let me tell ya, it's not hard. Altho im no pro, cause I lack experience, learning is easy. Forget paying