9" ?'s

PatrickG

Well-Known Member
Posts
226
Reaction
1
9\" ?\'s

I recently picked up a housing from a 67-77 Bronco to run in my toyota. When I called currie
to ask on pricing for parts they asked about the bearing size. I guess mine is a small bearing
and they told me mine is no good. What is the difference between the two and does it make
that much of a difference? Im going to be building it up to eventually run mdr 1450.

Patrick
 

jeff

Moderator
Posts
7,422
Reaction
314
Re: 9" ?\'s

Yes, it makes a big difference.

The "small bearing" version is considerably weaker. It would make no sense to build one up when you consider the price to build the big bearing version is the same or less. You can run a conversion bearing to run a 31-spline axleshaft in the small bearing tube if you really want to run that rear.

My advice would be to sell it and locate a big bearing version. If you just ABSOLUTELY have to use this rear end you can make it work... but it'll never be as strong as the big bearing version and you'll never have the same parts availability.

Aloha
 

TRDshaunTRD

Well-Known Member
Posts
1,061
Reaction
0
Re: 9\" ?\'s

whats the difference between them and how can you tell?

"Those who risk nothing, are nothing."
 

TRDshaunTRD

Well-Known Member
Posts
1,061
Reaction
0
Re: 9\" ?\'s

so based on that chart, the 9" to get is the "big ford"??

"Those who risk nothing, are nothing."
 

hoeker

Well-Known Member
Posts
2,004
Reaction
101
Re: 9" ?\'s

Not all early Bronco's are small bearing housings. i have a '76 that came with the big bearing. The willwood diagrams are nice, it's easy to check the bearing diameter 3.150 is the goal, so check that first, but they don't address the different bolt sizes ford used in some early housings. the newer ones are 3/8 bolts while the older ones were 1/2. bigger isn't necessarily better in this case either. i would much rather stick with the 3/8 bolts, they're plenty.
the biggest problem with early broncos is the small housing. i actually swapped mine out for a narrowed truck housing to reduce the need for trussing. if you're going to race it, you can truss either and make it work, but the later housing will end up lighter and stronger.
you can also cut the ends off the housing you have and install new ones to get the bigger size if you don't want to get a new housing. i did mine with a fixture i made on my lathe, but i'm sure there's a fab shop near you that can either narrow the truck hsg or change the bearing ends on the bronco hsg.
depending on the abuse you will give this truck you may want to consider going to a 40mm bearing, it's the same diameter, but a lot wider. this is what i ran in my CORR stock truck with MOSER axles. they don't break. 35 spline inner and one big bearing.

LIGHTS RIGHT
www.rosshoek.com
 

toddz

Well-Known Member
Posts
1,434
Reaction
175
Re: 9\" ?\'s

so based on that chart, the 9" to get is the "big ford"??
_______________________________________________

Yes. The 'big Ford(new style)" is what is referred to as the "Torino big bearing". It came on the '74-'75 Broncos as a "medium duty" rear end with big bearings and small brakes(10" vs. 11" for the standard big Ford). I'm a fan of the 1/2" vs. 3/8" bolts as well.

The only early Bronco rear end really worth considering for race work is the '77 unit, which is basically a narrowed pickup banjo unit. You can buy a newer, stronger version from Curries and others for not a whole lot of $$.

Todd Z.
 
Top