Just ANOTHER 8" question. Which is weaker: the 8" or the axles?

Back to Frank's point. (Which I thought was a good one)

... Scoop, how much HP are you making? What is wrong with the 8" setup you already have? An 8" saps less HP than a 9". An 8" has less rotation mass, weighs less over all, and less gear mash related friction (assumption). So unless you NEED to go to a 9" for durability concerns, why would you

I would stick with the 8" unless you have over 350 HP, have some hard hitting stall and chassis setup, or are going to a stick and plan on thrashing it. Lots of guys have claimed 11 second and better times with an 8". Add some aftermarket axles to a good chunk setup, and I believe it can handle most any high performance street/strip setup (within reason!).

 

I have 265 HP to the ground, c4 and currently stock stall, but just waiting for a 3000 converter to rear its ugnly head. 26X10.5 slicks.

With all the guys discussing broken axles and gears, why wait for mine to go out? Especially with all the guys telling me how bad a mini spool is and how it may snap the pin.

I would rather build up a 9" which I already have the housing, and not worry about breaking anything and/or hurting someone at the track.

Or I can take my chances and hope for the best, but I will sure feel like crap if I snap an axle and take out my car AND the car in the lane beside me.

Yes, I agree, my car isn't all that powerful and it has a forgiving transmission. And I don't use it at the track very often at all.

But if I have the housing I may as well use it someday. Then if I DO get lots of track time, I will have a rear that will NOT be the weakest link.

 

31 spline 9" carriers are easy to find ... a lot of trucks have them.

Get a swap meet center section if you want to build on a tight budget ... plenty of them out there. I would only pay to get one set of axles made once, and be done with that part of it.

The ease of swapping center sections is the best feature of Ford 8" and 9" rears. That is why you see so many Chevys running them.

I am on my third gearset, and my axle has never been out of the car. Boy, those 4:62s were big, stupid fun! (6 mpg too) ... looking forward to driving it with the 3:55s I just installed.

 

which trucks and which years? I will start to keep an eye out for them.

 

Here is a link to add to the confusion ...


http://www.ford-trucks.com/forums/897772-9-inch-axle-question.html

And a general info 9" link ...


http://www.kevinstang.com/Ninecase.htm

 

73-79 but seems most 400m trucks and all 460 cu in. And all 4wd are 31 and trac-loc regaurdless of engine size.