How strong is an 8 3/4 rear?

[General Ryan]

Hey experts, was wondering how tuff this rear is in regards to pumping up the power on the engine/tranny combo and what you should do to make the 8 3/4 take it without breaking.

With my plans for the engine build in the 600hp range and a tranny to take it, can the 8 3/4 take it?

I want to keep this rear end for a few reasons until I install a gear vendors unit.

I like the fact its a tough factory piece in comparisons to other manufactures and also because of the third member; in allowance to change rear gear ratios quickly, so if I choose to change it out at the track and then place my highway gears back in for the trip home.

Any advice to beef it up?

Thanks
Ryan

[y3chargerrt]

The fact that it came behind alot of automatic Hemi cars tells me its pretty tough. I don't kow about 600 hp tough though.

[Blown70]

In my reasearch I was told 600 to 650.  I have a Dana so I am not too worried, with what I am going to do.

You should be fine but I would either replace or make sure your axles are in good shape.

[firefighter3931]

The 83/4 is pretty tough. As long as you don't dead hook it the chances of survival are good. If you plan on running slicks and racing it....it's not a matter of if, but a matter of when....it will grenade. If this happens there's a good chance the transmission will blow because the sprage often fails when the rear end breaks sending the front drum to sky high rpms. When this happens it explodes and comes through the floor and can take your foot off...or worse. There's a reason racers use driveshaft loops and tranny blankets/trans shields.

The cone style suregrip units cannot take the same abuse as a clutch style. If you were intent on running the 83/4 behind 600hp i would suggest you look at an upgraded suregrip unit and aftermarket axles. The housing should be backbraced as well because it can flex and cause failure of the centersection. There are aftermarket caps available as well and those should be considered part of the upgrade. By the time you've done all these upgrades you will have spent as much as buying a Dana60 and still have a weaker rear. The combination of weight and big torque that a stroker makes is the issue.

Ron

[General Ryan]

WOW,
Once again, thanks Ron, very helpful

[firefighter3931]

WOW,
Once again, thanks Ron, very helpful

Ryan, check this thread out.....member sledge57 just broke his 83/4 with a 470ci stoker. He was lucky because the SG unit didn't fail....just one axle snapped.

Ron

http://www.dodgecharger.com/forum/index.php/topic,2616.0.html

[Ghoste]

And if you backbrace it, you may have to add the expense of having someone who knows what they're doing to weld it.  It's easy to bend the axle tubes if you weld the brace on wrong.

[cudaken]

 I used the tock style sure gipp with starnge axels for year's in the 68 Road Runner and was in the 11.8 range. But, hook up, well small 10" slicks, super stock springs, snubber, drag shock and unbolted the front sway bar and that was it. If, I had worked more on the back end she ould have been faster.

I never killed the 8 3/4 and God can not tell you how many passes I made. Would guess around 400. I may just be lucky, but never hooked up great. First 10 feet I had to back padle to keep the hides from lighting up.

But, that was also in 1976 or so and Runner only had 86,000 miles on her when I dropped in the 426 Maxie.

If or when I broke the 8 3/4 I would have installed a Dana, but never broke and did not need the extra 200 pounds. Hum, might have hooked up better?


                          Cuda Ken
Rather be safe than sorry and the bolt in sprag is a must as well.

                             

[Chryco Psycho]

it really comes down to tire spin generally the 8 3/4 will live If the tires spin , if you hook you might as well build the Dana now

[Rocky]

I don't want to hijack the thread, buy wont the stock axles break before the center section will?

[Ghoste]

Not necessarily.

[cudaken]

 I did twist the axels in the 8 3/4, that is why I went with the Strange Axels. Carrier never did give up the ghost.

                                   Cuda Ken

[Chryco Psycho]

I have scattered all of the parts , the sure grip gears & the ring & pinion & the axles

[KMPX2]

I have seen photo's of them in older dragesters

[Ghoste]

In all fairness though, a lot of those old dragsters would smoke the tires for the whole 1/4 mile.    If you did break one, you just got another one, they were as common as dirt at one time.