Is an 8 3/4 rear end good for all out drag racing, Anyone put turbo on 440?

[72cuda]

I was wondering what everyones opinion is on using an 8 3/4 rear end for drag racing. Also has anyone put a turbo or supercharger on a 440? If so, how and what turbo did you use? Any info would be helpful.
Thanks
1972 cuda

[rumblefish360]

For all out drag racing, I would not use an 8 3/4. I would use the allmighty Dana. The consumption diff. in HP is near nothing and the real exchange for useing the larger rear is durabilty.

There was a fella here, that did a twin turbo 440. His car was in MoparMuscle.
You can catch him at Moparts if he still freqebts the boards.
Stay tuned here as well.

[Woodchuck]

Heres his sit address

http://www.pentastarpower.com/feets/newpage.html

[rumblefish360]

Thats the fella.

[J-440]

Cuda, an 8 3/4 rear in my opinion is great for racing, although the Dana is even better. You got the money, go for it. If you do drag race with the 8, just do all the necessary strength mods and use high quality stuff and you'll be good to go. I will be s-charging my 440 in the future. Check out last issue's Mopar Action, a guy s-charged a 440 in a 77 Cordoba. With plenty of research, it should not be a problem.


J-440

[b-1ken]

I don't think an 8 3/4 is what you want for serious drag racing. If by all out you mean using a trans brake or a clutch car with 15" slicks on a well glued track, the best (from my point of view) is a Ford 9". A Dana 60 is strong, but it is NO fun to work on. The Ford 9" is a dream when it comes time to change gears. It is more expensive than a Dana, but to me it is well worth it. If you have other people set up the rear, then maybe a Dana would be better because it's cheaper and perhaps a bit stronger (debatable) and YOU won't have to work on it. At any rate, I would definitely NOT run an 8 3/4 if you're planning on leaving the starting line like most drag cars I'm familiar with. On the other hand if you're foot braking it (no trans brake) and have 500 hp or less, then It will last for a while.

[1fastski]

has anyone PRO charged the mopars ? i work with prochargers a lot in the marine feild ,but i only see them on chevys .i like the procharger for the reasion i want to keep it all under the hood :-)

that turbo was cool stuff to much work though .


chris

www.1fastski.com

[robs440]

funny.....they used 8 3/4 rear ends behinds hemis for a couple years before they started putting danas in the cars...... and they seemed to hold up just fine.

[rumblefish360]

J-440, robs440;

The 8 3/4 is great until it's HP level is passed. He (72cuda) asked an opion on drag racing but declined to give a performance level. Takeing a safer path, and a durable one, I chose the Dana.
The 8 3/4 came stock behind the Hemi for street. When is the last time you seen a Hemi pro racing with a 8 3/4? How long did it last? What did he then upgrade to?
I answer it like this;
1, Never
2, not to dang long.
3, DANA

If he's weekend racing, a 8 3/4 is fine.
If he's getting serious about matters.......DANA

[robs440]

I agree its better to use the DANA. and your right the 8 3/4 was used in hemi street applications. If he is super serious then yes....he should go with the DANA. It is worth the peace of mind. But the 8 3/4 is thougher than most people know.

saw a roadrunner once in Denver with a rear end in it i thought was an 8 3/4 but the owner told me it was fried when he bought the car. So when i asked what rear end he had in it (looked alot like the 8 3/4 at first glance) he told me it was a buick rear end. Now thats something i wouldnt even come close to using!!!

[rumblefish360]

A buick rear????? Welllll, thats hot rodding. Use what ya got.

[J-440]

I always thought that the strength comes from the type of axles you put in your car. As far as pumpkins go, I take it the Dana has a larger diameter than the 8? Therefore the gears have an overall bigger and stronger diameter? Have not studied rears too much, always heard that the Dana was top dog though.


J-440

[robs440]

yeah i forgot the exact size but i believe danas are 9 to 91/4".

I got a 3.91 8 3/4 rear from a truck but was running 14" tires then nd thought it was a little tall for all the highway driving I was doing so i traded a buddy for 3.55's. I got the better deal as the adjuster block that sits between the axles fell out and was floating in the gear lube. he never could get the axles to adust up properly!

[MJD]

8.75 if properly built will easily take 800 plus HP. I bought a 71 Duster 4 years ago and it has been a drag car since 85, the 8.75 in it had a suregrip and resplined axles. I pulled the rear and we checked it for straightness, tube ends were out by almost 1/4". I added a backbrace, cut the ends off and re-trued the tubes, added Strange axles and spool and have run the car for 4 years now with no troubles. Car has a 383 on nitrous with a best of 10.23@134, tires are 14.5x32x15 and the car leaves well. Rechecked the rearend for straightness last summer and it was dead on.

I don't think you can beat the 8.75 for durability, cost of pieces and serviceability.

BTW Robs440, a lot of old drag racers used the buick rearends, supposedly they were bullet-proof and you can still can get the parts for them (big $ though)

[dwc43]

[QUOTE]Originally posted by robs440
[B]yeah i forgot the exact size but i believe danas are 9 to 91/4".

The Dana 60 is a 9 3/4. The 9 1/4 is the truck rear like whats in my Ram.
The 8 3/4 is a great race piece. I have one in a '74 Duster 500 cid car. All aluminum engine,fiber front clip,deck,and bumpers. Coil front and rear with ladder bars welded to the 8 3/4 back braced and an aluminum carrier from Rand's Ring and Pinion. Tough set up. Tote the wheels easily.

[thecudaguy]

I've blown up two 8 3/4's with not alot of h'power. (719 to be exact)
If your going heavy then build heavy.

[robs440]

right you are guys..9 3/4

see how long its been since i had one? lol

had one in my truck in 84, nevr had to work on it.

Local racer here in town had a shortened dana in the rear of chevy chevette with a 327 chev he put in it. later put in a nasty 427 and a doug nash 5 spd. not much room in the chevette for that big block! 2 passes and blew the rear......he put something together wrong in the dana. Dont know why he wanted a 5 speed, he never got out of 3rd. Any ideas?

[thecudaguy]

His dana must have got a rash from the chevy.

[jussi308]

We have a 8 ¾ rear end in our car. In our application the rear end is used only in drag racing with transbrake. We have a 2900lbs car which was run with 526cid naturally aspirated engine producing 800hp. Our rearend is shortened to fit the 32x17.50-15 slicks and the banjo is strengthened and has also backbrace. It has pro street gears in (but they have been heat treated in a big oven). Moser 35spline spool and Strange Pro Drag driveshafts with 5/8 bolts. Also there are Mark Williams steel replacement main caps. The case is 489.

We are now thinking to get a 9” Ford because our new 477cid engine produces 1000hp naturally aspirated and has also nitrous set from 250 to 500hp. Or could the 742 case with Pro Drag gears handle the power. If and when we swap the rearend it’s going to be Ford beacause of its strenght and maintainability.

Suggestions?

[nhdriver]

Originally Posted by b-1ken

I don't think an 8 3/4 is what you want for serious drag racing. If by all out you mean using a trans brake or a clutch car with 15" slicks on a well glued track, the best (from my point of view) is a Ford 9". A Dana 60 is strong, but it is NO fun to work on. The Ford 9" is a dream when it comes time to change gears. It is more expensive than a Dana, but to me it is well worth it. If you have other people set up the rear, then maybe a Dana would be better because it's cheaper and perhaps a bit stronger (debatable) and YOU won't have to work on it. At any rate, I would definitely NOT run an 8 3/4 if you're planning on leaving the starting line like most drag cars I'm familiar with. On the other hand if you're foot braking it (no trans brake) and have 500 hp or less, then It will last for a while.

I totally agree w/ Ken on this, but would also add that once you get into higher numeric ratios 5:13 & above the physical size of the ring gear tooth gets smaller (as the pinion gear gets larger ) The result is usually broken teeth on the ring gear.& a broken rear end. The Dana 60 is way stronger (as is the Ford 9") It comes down to cost (Dana) vs. ease of set up & maintenance. (Ford 9")

[Cudadrag]

I have and have had both a Dana 60 and an 8 3/4. In the Duster the 8 3/4 with the Mosier 35 spline axles and spool has held up very well. The car has blown yokes and twisted a driveshaft but the 8 3/4 is holding strong. It's far easier to replace gears than the Dana. It's lighter with less rotating weight than the Dana. I'm confident with the Mosier axle kit & spool the 8 3/4 can handle up towards 1000 horse. If you plan to go higher than that then a Dana with the Strange Pro gear package which they rate to 2500 horse. Anything over that then an after market 10/11"

[nhdriver]

I ran 8 3/4 rears in my drag car for years using 4:56 & 4:89 ratio's the would typically last for a full season & a half before something would break (usually the teeth on the ring gear would crack & break off ) I then re-tubbed my car and went with much taller & wider tires the 5:13 gears (brand new) went about 5 runs before it broke. I put a Dana in the car & ran it for the next 3 seasons w/ NO breakage. I sold the car & it went another whole season before any failure occurred. I wouldn't put a lot of money into an 8 3/4 rear (you certainly can w/ aftermarket caps, braces etc), I would go with a Ford 9" or a Dana 60 first.

[jussi308]

Decision is made. We'll using transbrake all the time on well clued tracks so we'll updating to 9 1/2" Prisma rearend (type Pro Mod) with 40 spline gun drilled axles. So I hope that with our max horsepower of about 1400-1500 (with NOS) cant break it. Banjo is made by Jerry Bickel race Cars but the rearend is not a floater.

[Cudadrag]

Originally Posted by jussi308

Decision is made. We'll using transbrake all the time on well clued tracks so we'll updating to 9 1/2" Prisma rearend (type Pro Mod) with 40 spline gun drilled axles. So I hope that with our max horsepower of about 1400-1500 (with NOS) cant break it. Banjo is made by Jerry Bickel race Cars but the rearend is not a floater.

You ae putting some real power to it thus definatly outside the range of an 8 3/4" rear. Fortuantly there are plenty of option including a 9.5. What trans are you looking to use? This much power is also typically outside a 727's range. Powerglide?

[jussi308]

Originally Posted by Cudadrag

You ae putting some real power to it thus definatly outside the range of an 8 3/4" rear. Fortuantly there are plenty of option including a 9.5. What trans are you looking to use? This much power is also typically outside a 727's range. Powerglide?

We're now using Powerglide with JW SFI case and inner parts rated for approx. 1500 hp.

[jussi308]

Last year our best ET was modest 9.323 in 1/4 mile. We had some traction problems cause we were newbies in adjusting 4-links. Before that we had ladder bars and leaf springs. Now 4-link, wishbone and coil-over suspension. So it takes some time and investigation to get the hp in track.