rear end choices

I am looking at beefing up the drive shaft and rear end in my drag car and wanted to hear opinions.

What is the car?
1970 Satellite 440 footbrake/7.0 index 1/8th mile car
Current HP roughly 450 with plans to go to 550 HP over the next two years
Car weighs 2860 lbs empty and 3100 with me in it
Using Hoosier 29x9.0 radial drag slicks
Current set-up is an 8 3/4 489 w/4.88 gear stock posi unit
Drive shaft is stock
Pinion snubber
Stock springs
Stock axles

Options:
I have another 489 w/4.56 gear on a spool
I also have an empty 8 3/4 housing
I am thinking of building this and adding Calvert racing springs & Caltracs
If I did this, I would buy next Strange axels and probably upgrade the yoke to a 1350

My second choice would be to simply buy a new Dana set-up from Strange

Obviously the second option would be more expensive, but since I am planning to change the springs to Calvert and upgrade the yoke either way, I wondered should I build the 8 3/4 or not?
The advantages I see to the 8 3/4 would be:
1. Weight
2. Cost
3. Flexibility in changing gears, (this does matter as I usually run 1/8th mile, but would like the option of running a 1/4). If I bought the Dana, I could always keep the 8 3/4 I have and put a 4.10 gear in it for 1/4 mile runs. IS it easier to swap the center chunk from an 8 3/4 or swap the two setups out all together?

It comes down to either spending the $700-$800 on the axles and yoke for a 8 3/4 or using this money towards buying a Dana.

The question is, How would you compare a 489 8 3/4 with a 1350 yoke and spool and Strange racing axles to the Strange Dana?

What would you do?

Get a S60, D60 & a driveshaft from Mark Williams , I learned the hard way with the 8 3/4, AND Mark Williams can spin the driveshaft to the RPM that your combo runs for the balance, others can only spin them 500 rpm, another expensive lesson learned, all said I wasted about $2700 on blown up 8 3/4's & chasing a drive line vibration, its all fixed now !!!!!!

I'm seriously considering going to an aftermarket 9". Easier to change and more "pro gear" ratios available.

Well, we have a few of each running around. I prefer a Dana, but if 8-03/4 is what you got, a back brace is required, and billet main caps with ARP studs is the min for upgrades...On top of good axles...

I wouldn't spend any money on a 8 3/4 rearend for a drag race car. Either put a Dana 60 in it or just convert now to a 9 inch. Sell all of your 8 3/4 stuff to fund the switch. The Dana 60 is a little less expensive than a 9 inch but not as easy to get parts for. If you are sticking with deep gears then a Dana 60 will work okay. A 9 inch is well suited for the bigger buck cars that are making more power and going faster.

500+ hp, relatively heavy car...

60 or a 9", no debate. Throwing out all the arguments - cost, Ferd parts in a Mopar, etc, - 9" all day long.

If you decide to use the 8 3/4 make sure and have a back brace welded full length on before installing the axles and third member. Make sure and check it for warpage after and if it is warped have it straighten before racing it
If it was me in your shoes and knowing what I have learned the hard way on rear ends and drag racing I would start with a narrowed Dana 60 with 35 spline axles and a spool and skip the Cal Tracs and go straight to ladder bars with a good set of double adjustable coil over shocks so you can put a bigger set of tires and wheels on it later when you want
It may take you a little longer and cost a little more now than later but do you want to do this twice.
I did

Actually, that's pretty light for a B body of that era.
Nevertheless, I'd go directly to a Dana 60, or a braced 9" if you really need to swap ratios.
Rearend breakage never ends well; keeping the car off the walls never goes out of fashion.
I'd check with Dr Diff, Cass has been very good to deal with.
Good idea to upgrade to Caltracs & 1350s.

THIS!!! You can convert a truck/van Dana 60 for a lot less than the S60 costs. The S60 is really nice though w/ those side adjusters.

regarding the gear swap issue, I've set up multiple sets in one D60 housing, and stored the shims, bearings and gears(with spool) set together for future quick swap in that housing. Once you have the shims required its just preload and verify BL.

Thanks to everyone. Cab I am always interested to see what you have to say. I agree that fixing it once and doing it right is probably the best option. It seems unanimous that you all believe the 9" or Dana is the way to go, and if I am going to do it, I might as well do like Cab said and go ahead and narrow it and change the suspension once. My budget is not unlimited and it will require me to hold off on other upgrades, but until I have replaced the drive shaft and rear end, I do not think I want to push for any more than 500 HP.


Thanks to all who responded.

Do the Super A cars still run the 12 bolt Chebby ?

Supposedly the less parasitic drag of any rear end out there ....,with decent strength in the package

Not since you were a pup.

Pro Stock tech 9". Ceramic bearings, Lightweight, titanium, REM, etc.

Rules say OEM type housing only. No 100% fabbed sheetmetal housing. Don't know if the tech guys get down on their hands and knees and look anymore though. Prolly not on the shootout cars.

Big block/Hemi Stockers use a 60 with good parts..

Well Mr Helpful ... which rear end has the less drag ?

A mopar 7.5

7.5 ?

Ever spin the yoke on a good Dewco unit?

On stock style units with standard bearings, preload, etc, the pinion being low on the ring gear is a disadvantage due to drag. Gear design and treatment, the best bearings, set up, etc., pretty much eliminates that.

Aftermarket parts, support and development, ratios, etc makes it a no brainer. Just like engine, chassis and everything else tech, that stuff flows downhill to the lowly bracket and class racer.

The 9", and designs based on it, are standard issue for everything up to the real fast stuff.

Do you have a list of the bester ones and drag numbers ?

I’ve got a 12 bolt in that 27 roadster....

I don't.

If it blows up the first time you take your thumb off the button, it doesn't really matter how efficient it is.

M I right?

I broke, rebuilt, broke, rebuilt and broke again my 8-3/4 over the past 5 years. The second time I fixed it, I did it right with a backbrace, 35-spline spool and steel maincaps. It seemed to be just fine set up like that. This latest breakage really wasn’t the fault of anything in the rear end, but my welds on the spring perches broke, and carnage ensued. I finally decided I wasn’t going to spend any more money on the 8-3/4”. I had a local racer buddy build me a Dana for a little less than an S60, and I’m really happy with that decision, as now I can move on to other needs with the car without ever worrying about the rear end again.

My experience is that weight kills 8-3/4’s. If it were an A-body you were working with, I might say the 8-3/4 is worthy of investment. In a B-Body, I’d suggest moving to the Dana. 9” in a 70 B-body???…. Nah.

Weight, horsepower, trans configuration, radials or bias, track prep.

stealthyWedgie .. with all those issues ... I would have probably just have said FUGG IT and gone with a Dana 70 .,..out of a dump truck or motor homey!

I build my own Dana's from truck stuff. Cost me right around $1000, plus a core housing. The latest super duper 9" is great, but expensive. At 550hp 2900lb, foot brake? A 8 3/4 will go a longtime. My street/strip car weighs 3885 and runs 11.0s. It's never hurt the 8 3/4. Been racing it on/off since the 90's. Pure race at normal bracket race power level? Dana is the most cost effective.
Doug

[quote][/quote]

seaMac... supposedly 1800 lbs - at the starting line ... 500 hp(change oil once a season) ... footbrake trans ... big meats and good hook .... ?

Thanks dvw. I kind of agree and if I truly felt I would never want to go beyond footbrake I think the 8 3/4 is the best option.

But like everyone else, I know once I go 6.9 in the 1/8th, I will want 6.8. If I get used to 6.8 I will want 6.5, then after running there a few months, surely 6.4 is within reach. After that, I would need to upgrade the car due to safety rules, and of course, once that is done, running the 6.0 index would make the most sense, but then I would want that time slip showing the car in the 5's and, well as you can see, this never ends.

When it comes to my racing, I have not yet found my limit, and each time I think I felt a real thrill, my thirst for more comes back! I have driven cars significantly faster than mine and am not scared.

I doubt I will ever be that consistent driver who runs for points or is satisfied with a car that is always steady and perfect week after week.
I also do not have unlimited funds, so budget is always a consideration.
I am not a car builder, this is simply an amazing hobby for me. Unlike many folks here, I do not even work in the automotive industry.

With that in mind, I am thinking "Build a car that I could run about any engine in from a safety perspective, with a heavy duty drive shaft, rear end, axles and a cage that will be safe for anyone who drives it,"
(I am old enough now to realize this car should out live me, and I want to leave it a safe and fast as possible for my future family member, whoever that maybe)

Then depending on how life plays out, I can focus on the engine. I like the idea of fixing the rear-end once and being done.

I broke a few 8 3/4" ring & pinions in my Dart Sport footbraking. But it weighed 3,540+ lbs with a best of 1.47 60', 11.14/6,99 ET and 117+ in the 1/4, wheels up almost every time. That's the weak link as I never broke a cap. I finally got a pair of Moser Dana 60's for the Dart and a slower but heavier Aspen wagon, but never got the Dana put in the Dart. Just wanted peace-of-mind and knew the optimum ratio. Could have easily lost my IHRA Stock championship in 2017, but the timing of the break, some particularly high points-earning wins and a few incredibly lucky breaks otherwise made it all work out.

so how much hp can a guy have before a dana is needed in my charger ? 350 ? 400 ?
just getting an idea so i can save up for one........
i know a new driveshaft with 1350 yokes is in my future, but i don't want to have to buy two of them. although i have thought about spacing the rear back about 3/8-1/2" to center the wheels in the quarter openings. would that allow the 8 3/4 driveshaft to fit the dana ?
i'm hoping traction will be an issue at first, saving the rear.
i know this heavy tank won't be a 10 second car, but i don't want to be fixing things that make big chunks and bad noises all the time.

What I have found is when you launch & it spins & then it bites is what will KILL an 8 3/4 even at lower HP #'s & weight , so just don't ever spin the tires

Weight / Torque / Traction can kill a Dana too....

Some guys can screw up a 50 ton wrecking ball in a sand box with a feather, huh JUST KIDDING

You could use a 7.25 in that. We used to call them "sissy rears". Guys would cut them down, weld the gears up, and use them in Cub Cadets with a 2 cylinder Kohler for lawn mower pulling.

8.75 should live in that. 12 bolt, even a 10 bolt GM. 8.8 Ferd would work. Easier to find, cheaper than an 8.75.

Or just get all aftermarket 8.75 stuff. Moser does a housing. Randys does a center.

I’ll get that up on the rack and pull the cover .... supposed to be a big $ 12 bolt !

Well when YOU were a young gEeZeR .. those 12 bolts were goodies ?

I run the alum 8 3/4 in my race car but the car is light.. runs 8.90s and has a 1.19 60 ft.. I also run the
9" in my street rod set up to run 10.0.. both cars are back braced.. heavy cars will break parts so if
you can make the car lighter you should

And plentiful. Like 340s. Couldn't walk from one side of the shop to the other without tripping over one.