axle strength with v-8

I have a 69 cj-5. I have not driven the thing. Been working on it for almost two years. The po used to sand drag race it, put in a 67, or 68 chevy 327, he says it should have about 400 hp. like I said i havent driven it yet so I cant say if he is probably right. It still has the 27 front and off set 44 rear. gearing is 4.88 and there is some type of traction device in both diffs. question is do you think these axles will be toast with that motor in it. I would think they would have been toast a long time ago especially with him sand dragging it. would eventually like to put some waggy 44's in it with wrangler springs, sprung under, but untill then do you think these will live??? thanks.

 

Depends on how you drive it. If you try 2-wheel or 4-wheel burnouts on pavement, they will break. If you jump it under full throttle, they will break. If you put huge tires on it and go full-throttle in the rocks, they will break.

If you drive on dirt roads and mild trails, and feather the throttle, they will survive.

Between those extremes is a gray area. In that zone, everything depends on your discretion with the throttle, the situation, and a little luck.

Any drivetrain setup can be broken, given the right situation.

 

I ran the stock axles (25/44) in my 3B with a 327 without problems. That engine wasn't exactly mild (big heads, 11:1, 7k solid lifter cam), but was a long ways from 400hp. What it comes down too is your use of the trottle-a little restraint and things will stay together-at least for a while. A 400 hp 327 would be a VERY healthy one in terms of hp but will likely be near worthless off road-too much cam for any bottom end torque. If it was mine, I would see if I could get the cam specs from the PO and change it out if it is greater than about 215 degrees at .050.

My guess is the trans will go first, the 2 piece axles next, if you have a heavy right foot, assuming you keep the tires at 31 or less. The D27 in my 69 went to pieces with just the 225 and no locker with 31's.

 

old timers dragged the heck out of these CJs
some guys broke all the time...others didn't

 

Sounds very much like my Jeep, but I can almost guarantee you that if you’re running cast iron heads and pump gas you’re not getting 400 horses out of it.
Not to imply these little mouse motors are weak but getting better than 1.22 HP per cubic inch on pump gas is performing some mechanical magic.
Still, a hot 327 can quickly overwhelm stock (ish) Jeep axles but like Tim already said, how long your axles survive depends on throttle to brain ratio.
Just so you know though, I’m running a fairly hot 327 (bored .030 over, 10.5:1 CR, forged bottom end, roller top end) with a stock-ish Dana 25 front and a full float converted Dana 44 rear. Both have 33” tires, 4.27 gears, Power Lok Limited Slips, and I have had very few problems with the rear. The vast majority of axle issues I’ve had have been with the Dana 25 front and all of those issues were related to throttle to brain ratio. Mainly, don’t hop the front end. If you’re spinning tires and the front starts hopping get out of the throttle. The shock loading will tear it up quickly.

 

On the rear axle, take the nut off the end, weld the hub to the axle shaft, and voila, instant flanged axle.

 

I'd say for a sand dragger, it might have been fine. Not nearly as much shock load in the sand than in the rocks.......

 

Not a good idea in anyway!!!!

 

The flanged AMC 20 in the Wagoneer and J-10 is welded, but it can still be removed from the housing. Supposedly the whole assembly was heat-treated after the flange was welded on. My understanding is that welding the hub to the axle (without subsequent annealing / heat treating) will stress the axle at the weld and it will break next to the weld.

 

thanks for the responses. I will just take it easy with the gas pedal for now. Im not sure I buy the 400 hp, to hear it run it doesnt sound like anything special, i do know it has the old fullie heads, thats all I know. long story short I got the jeep from my brother and have no way to contact PO. we have tried. The trany is another mystery. Know one knows what it is, even the local off road shop couldnt identify it,but I will post more on that when I get it driving.

 

A local jeep racer told me that when I was asking him for advice on locking my axles. He said the key would break and the hub would just spin on the axle shaft. Makes sense to me.

 

That's what mine has also.
I've also heard them called Camel Back, Double Hump and Power Pack heads.
Stock most 327’s with Power Pack heads were making around 300 horses at about 5600-5800 RPM. The Corvette versions had more cam, a bigger intake and were making around 350 HP at 6200 RPM. Seems like the big dog back then was the mechanical fuel injected version that made something like 370 horses at 6400 RPM, so they can make some power but you have to rev the pee wadding out of them to get it. Which is actually what I dig about 327's, they’re a short stroke motor so they come on the revs quickly.

Post pictures here and I'll bet these guys can figure it out.
But it wouldn't surprise me a bit, from the sounds of your motor, if you've got a Borg Warner T-10 just like mine had in it. They're a short throw 4 speed meant to keep a high strung engine on the boil. They were fairly common in 60's GM sport and muscle cars but the first gear, depending on application, was only a 2.84-2.48:1. Great for sand or street, sucks for crawling.

 

power packs are a little different than double hump heads aka camel backs, double humps were on the 350hp 327's, power packs are a lower hp but more torque at the lower end.

 

Yup. I used to do second gear wheelies with mine on asphalt (stupid, I don't recommend it). Never twisted the axle in hub but I always made sure the nut was torqued properly and checked them periodically. I twisted several 19 spline shafts at the inner splines though. Never broke one, but pretzeled the splines on several short shafts.

 

I agree with this statement. Seen it on tons of AMC 20's that were welded (not by the factory) and quite a few CJ-44's with tapered axles that had been welded.
The factory welded AMC 20's from the Waggy's were annealed, welded, stress relieved, then heat treated and hold up quite well.
Different than just welding a stock axle to the hub.

 

corveeper, our jeeps sound very similar. The jeep is at my parents house for use of their garage, so I will get some pics of the trany, but may take a couple days untill I get over there. here is alittle about it though. It is side shifted, the previous owner called it a rockcrusher 4sp. It looks all aluminum, is completly sealed, I see no way of getting inside with out slideing out the gears. it has no drain plug and the fill plug looks like it has been ground down. reverse is to the left and up(next to 1st.). when I get the pics, should I post a new thread about it or just post them to this thread? look forward to getting some input on the trany. thanks!

 

There are big and small valve heads (small valve heads are 1.94/1.50, big valve heads are 2.02/1.60) in that group but I hadn't heard of them differentiated by name like that.
Though I have been learning that the Power Pack option goes further back than I knew, to the '50's Bel Air, so I'm certainly not the final authority here. Just spreading what I've learned so far.

 

Yea, they sound very similar.
Mine was originally a California Jeep that my uncle built to run the dunes and tow behind his Winnebago when he lived there. After he retired to Oklahoma, where all that side of my family lives, he sold it to me and it's been a rewarding adventure to slowly turn it into a Kansas Jeep. :driving:
Aluminum case and side shifter is consistent with a B/W T-10. I can't remember what the shift pattern was on my T-10, it's been too long since it's been in my Jeep, but it seems like I remember it having both fill and drain plugs. IIRC a "rock crusher" refers to a Muncie transmission though. Anyone know for sure?

 

Yes the Muncie 4 speeds and the 4 speed A833 used behind Hemi's were referred to as rockcrushers.