GoFastBroncos.com

I want to buy and put a 9 inch under the bronco instead of the 8.8 with 4:88 gearing. My question is what is the best year to pull one from or does It really matter? I have a guy with a 9inch from a 84 bronco for 300.

80-85/86 are all the same. Cast case, 31 spline, 90% were 3.50 gears with some having a limited slip. The earlier axles have a different bearing end but are no better or worse.

For a built axle almost nothing is used from a stocker. Housing is weak compared to after market, both the stock cases and stock limited slips are known to break.

Be aware of the VSS issue too.... if your truck has a E4OD it's very important that the VSS work.

How wide is the econoline rear end then the stock 8.8? I'm going 4.5" wider per side with my ttb. Will the van housing match up good? Or should I buy a new 9" from shriener for 1800+.

From what I've heard the Econoline housing has thinner tubes and 28spline axles vs 31 in the Bronco ... Housing is 4" wider overall

robertcrav wrote:From what I've heard the Econoline housing has thinner tubes and 28spline axles vs 31 in the Bronco ... Housing is 4" wider overall

I thought 3" wider. 62.5 vs 59.5". May be wrong.....didn't research thoroughly.

One other thing to note, a Currie xtreme duty housing is 400 from Currie. Big bearing end, 3.5" tubes that are .250.

I used this chart I found
Outside
WidthYearModel
56.50 1969-1977Maverick 8"
57.00 1974-1978Mustang II 8"
57.25 1957-1959Ford, Ranchero, Station Wagon
57.25 1965-1966Mustang
58.00 1966-1977Bronco
58.00 1964-1965Falcon
58.00 1977-1981Granada/Versailles
58.50 1977-1981Versailles
59.25 1967-1970Mustang, Fairlane, Comet, Cougar
60.00 1967Cougar
60.00 1958-1960Edsel
61.00 1964-1971Ford Full Size
61.00 1949-1951Mercury
61.25 1957-1972Ford F-100 Pickup
61.25 1960-1964Ford Full Size
61.25 1971-1973Mustang
61.25 1967-1973Torino, Ranchero, Fairlane
63.00 1970-1979Ranchero & Torino
63.00 1972-1979Ford Full Size & Intermediate
63.50 1967Fairlane (Coil Springs)
65.25 1973-1986Ford F-150 Pickup
65.25 1978-1986Bronco
65.25 1973-1986Ford Van 3/4 Ton
68.00 1972Ford Van 3/4 Ton
69.25 1977-1986Ford E-150 Van

Doesn't the van housing have a weird 3rd member offset?

What width is ideal for a 4.5" per side front ttb? 68" wms or 70" wms? I'd like to get on ordering my rearend soon. As it's the only thing left for my rear to be complete.

Andy Jones wrote:What width is ideal for a 4.5" per side front ttb? 68" wms or 70" wms? I'd like to get on ordering my rearend soon. As it's the only thing left for my rear to be complete.

What Fiberglass are you going too be running Andy? I know with my Fiberwex bedsides the widest I could go on my rearend was going too be 69 1/4" with 17" Methods.

robertcrav wrote:From what I've heard the Econoline housing has thinner tubes and 28spline axles vs 31 in the Bronco ... Housing is 4" wider overall

Some of the early 80s Econo rearends came in 3/16" wall and 31 spline. I use those rear ends all day long for the guys on a budget. They are a dime a dozen and super cheap. Driveshaft is off too the side about 1 1/4 or so when installed in a Bronco. Cant tell though..

Threat Motorsports wrote:

robertcrav wrote:From what I've heard the Econoline housing has thinner tubes and 28spline axles vs 31 in the Bronco ... Housing is 4" wider overall

Some of the early 80s Econo rearends came in 3/16" wall and 31 spline. I use those rear ends all day long for the guys on a budget. They are a dime a dozen and super cheap. Driveshaft is off too the side about 1 1/4 or so when installed in a Bronco. Cant tell though..

Are these ones any wider than a stock bronco? I'd like to be roughly 2" wider per side and I'm cheap.

Threat Motorsports wrote:

Andy Jones wrote:What width is ideal for a 4.5" per side front ttb? 68" wms or 70" wms? I'd like to get on ordering my rearend soon. As it's the only thing left for my rear to be complete.

What Fiberglass are you going too be running Andy? I know with my Fiberwex bedsides the widest I could go on my rearend was going too be 69 1/4" with 17" Methods.

I'm gonna go with the fiberwerx ones and 17" methods or prt (ultras) . I'll order up a new shriner(sp) full floater 68" wms to wms.

Some van housings have a big offset, others do not. I don't know what years are what.

I just went through my rear end debockle. Here is my $0.02...
Econoline - 67.5" WMS
Bronco - 65.5" WMS
=2" wider
It's more common to find a 28 spline and I called around everywhere to get a part number for 31 spline replacement with no luck. Bronco/F150 housings are a dime a dozen. If you want wider its gonna cost $$.

I thought the 28 spline had 5x4.5 lug pattern. Could be wrong. I would rupn an aftermarket housing if it were me, prob an aftermarket 3rd too.

Unless the 8.8 is totally done I'd run it

28 spline 9" Econoline came in both 4.5 and 5.5 BC. In the early 80 you could buy an F100 with a 9" and 4.5 BC too.

Ford has done a lot of odd things in the past.

Interesting stuff here. How do the 9in and 8.8 stack up for weight in terms of unsprung mass. From what I'm seeing online, the 9in with drums is heavier by 45 lbs. The gvwr for both axles is the exact same. Those ratings could be subjective though.

They are the same weight until you add aftermarket housings, 35 spline axles, and huge trusses into the mix.

True that! I think ill run my 8.8 till its good and dead and then I think ill take a page outa yikes book and swap to 10.25 floater. Not convinced on 9in and I doubt ill have the mass $$ for a built 9