Author Topic: 8 inch rear end  (Read 20031 times)

ballajb

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8 inch rear end
« on: February 17, 2009, 03:32:07 PM »
I am doin the EFI swap into my Mustang. I have a built motor that will put out maybe around 325rwhp. Will my 8 inch rear end stand up to this power?

66GTKFB

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Re: 8 inch rear end
« Reply #1 on: February 17, 2009, 04:20:07 PM »
An 8 inch rear axle assembly will easily handle 500 hp. I would recomend a set of 3.55 gears and consider a rebuild in the near future.
Jim

ballajb

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Re: 8 inch rear end
« Reply #2 on: February 17, 2009, 04:49:45 PM »
oh ok, yea i plan on gettin a posi unit and gears but just was wondering how it would hold up for

Soaring

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Re: 8 inch rear end
« Reply #3 on: February 17, 2009, 09:57:59 PM »
oh ok, yea i plan on gettin a posi unit and gears but just was wondering how it would hold up for
If you happen to have a 9 incher laying around and don't have to buy one, then use it.  Otherwise Jim is right.   Gears and posi and you will be rock and rolling. 

macstang2

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Re: 8 inch rear end
« Reply #4 on: February 21, 2009, 12:00:00 PM »
oh ok, yea i plan on gettin a posi unit and gears but just was wondering how it would hold up for
If you happen to have a 9 incher laying around and don't have to buy one, then use it.  Otherwise Jim is right.   Gears and posi and you will be rock and rolling.
Don't bother with the 9", the 8" uses the same internals as the small bearing 9", I run the stock 8" in my 77 mustang II which came with stock 3.55 gears. I use 4.10 gears and a mini spool now with 400hp and 275/50R15 nitto's no problems.

treading

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Re: 8 inch rear end
« Reply #5 on: April 14, 2009, 09:12:32 PM »
What about an 8.8 Explorer rear end? I have an 8" without posi and I have been researhing articles and local scrap yards and have found a 95 Explorer rear end with 373 gears and posi for $250. Haven't bought it yet but it seems like a cheap way to get a stronger rear end as well as posi.

Soaring

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Re: 8 inch rear end
« Reply #6 on: April 14, 2009, 10:23:05 PM »
Take some measurements to determine if the 8.8 will fit.  I doubt that it will without some sort of mods.  Yours is right at 57" total from flange to flange,  and the 8.8 has to be longer. therefore making your rear tires rub.  Google the length of 8.8 rear axles and see just how long the axle is.   Your spring perch to spring perch as measured from the middle of the perches is 43".   

treading

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Re: 8 inch rear end
« Reply #7 on: April 15, 2009, 06:04:16 AM »
Soaring - from what I have researched the Explorer rear axle is 59.75" with a 2 3/16" offset on the right side. The Mustang is 57.25. One side of the axle would have to be cut to bring the axle width to specs for the Mustang. I know this would require a new axle for the shortened end as well as rewelding the tube housing. I have an accomplished welder in our family. I also realize that the shock and spring mounts would have to be cut or grinded off the 8.8" axle and new ones welded on the match the Mustang shock and leaf spring as well as 3.25" axle u-bolts. I will also have my original axle assembly for exact measurements for building the new one. The spring perches and shock mounts I have already priced as well as the new u-bolts. The 8.8" Explorer rear axle assembly is $250 - $300 depending on the year. The other parts including new axle will roughly run $300. If I go with C-clamp eliminators thats another $180. I'm hopefully looking at maybe $800 for the finished axle. I don't think I have missed anything. Do you foresee any snags I may run into?

Soaring

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Re: 8 inch rear end
« Reply #8 on: April 15, 2009, 08:03:20 AM »
Like I said, you will most likely have to make some mods for it to fit.  But, that will work.  Sounds like you have it figured out.  Where are you going to get that new shorter axle?

treading

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Re: 8 inch rear end
« Reply #9 on: April 15, 2009, 06:16:15 PM »
Soaring - I will have to wait and see exactly what length axle I will need. There's an E-bay store that has individual axles for around $90. When I go to this place in Orlando to pick up the Explorer rear end I'll ask if they have odd 31 spline axles with ford 5 bolt x 4.5 spacing, and if worse comes to worse there's a local speed shop that I've heard can shorten axles. First step is to get the Rear end, cut or grind off all the old perches and shock mounts and then clean up the pumpkin and tubes and get exact measurements from the old rear end.  I Had planned on starting a gallery and I will add to the gallery as I upgrade the Coupe.

rmodel65

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Re: 8 inch rear end
« Reply #10 on: April 16, 2009, 01:32:00 PM »
the explorer rear axle has an off set pumpkin

treading

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8.8" Offset
« Reply #11 on: April 16, 2009, 05:54:07 PM »
You are correct about the offset. The explorer axle width is 59.75 with a 2.48 offset to the right. The Mustang axle has a width of 57.25. I plan on cutting the difference out of the explorer axle to get the 57.25 width for the mustang. I plan on making the cut at the point where the new Spring plate will be welded. Then all I have to do is get a 31 spline axle to fit the new right side of the axle. Currie makes them to order.

Soaring

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Re: 8 inch rear end
« Reply #12 on: April 16, 2009, 07:10:07 PM »
You are correct about the offset. The explorer axle width is 59.75 with a 2.48 offset to the right. The Mustang axle has a width of 57.25. I plan on cutting the difference out of the explorer axle to get the 57.25 width for the mustang. I plan on making the cut at the point where the new Spring plate will be welded. Then all I have to do is get a 31 spline axle to fit the new right side of the axle. Currie makes them to order.
Sounds like you have your shit together.  Go for it bro'

 

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