Ford 9" or GM 12-bolt

[87BlackSheep]

Okay it's guns of the west here but I've heard this and that about both rear-ends. So I have a high probabilty of putting ~400 horsepower to the diff and I'm gonna get 4.10 gears, Detroit Locker, and 35-spline chromoly shafts (moser, strange, etc.). Does it really take more horsepower to turn the Ford?

 

[G_Body_Enthusiast]

i just read an article this morning in an old issue of CHP where they discussed the 10 bolt and how it's not as weak as people think, they were behind LS engines in the f-body so they cant be all that bad considering how much power those make.

proper planning plus a rear girdle with studs to keep the caps from flexing helps a lot.

they found it's cheaper to stick with the 10 bolt and it will hold up fine if you build it right. it doesnt need exotic parts either.

 

[87BlackSheep]

I'll have to keep that in mind. but I've been thinking about a lot of rear-end upgrades for the engine and wheel/tire assembies. I'm gonna get the Irocs custom widened to fit a bigger tire with wheel spacers. More metal/rubber means more torque applied.

 

[87BlackSheep]

 

[Blue86Monte]

If you going to put that much power I myself would not keep the stock rear. 12 bols and 9 inchs can be built to handle some extreme power. I think it all comes down to prefrences, I bought a 9inch and calld it a day...

 

[JBreu]

CHP did a test last year with the Ford 9", Dana and Chevy 12 Bolt rears..Guess what??? The end was that they pretty much werre all around the same area when it came to strength...........If it were me , go with a 12 bolt rear....I have one myself....Nothing against the 9" rear..Just preference....I say keep your GM car all GM 8) The 12 bolt rear is a pretty much bolt in deal...you will need different upper control arms for the a to g body swap, from UMI Perfromance or Iceman Racing....But in my '79 Monte I had, I bolted in a 12 bolt from a '72 Elky using all stock stuff...never had an issue there.

 

[87BlackSheep]

thanx. thats pretty helpful. Yeah it does sound good to keep it a 12-bolt. I'm gonna upgrade to hotchkis suspension like in the grand nationals.

 

[Blake442]

Either Car Craft or Hot Rod did a comparison a few years back between the Chevy 12-bolt, the Ford 9", and the Dana 60.
They put them all in the same car, and ran it on the chassis dyno.

The 12-bolt is not only the lightest, but it absorbed the least amount of hp, making the biggest numbers at the wheels.
The 9" was very close behind, followed by the Dana 60.

It really boils down to cost.
Sure, you can put in a '68-'72 12-bolt in with aftermarket upper arms and different off-set wheels, but by the time you spend all that money, you could've just bought the direct bolt-in unit from Moser. We put one in a Monte SS we built at the shop I used to work at, I think it was like $1500 complete with everything but brakes.

Ford 9" are great because they're not only easier to find, but they're easy to swap gear-sets, and you can weld all the brackets right on them, unlike the cast center section of the 12-bolt, which helps keep the cost down.