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Educate me on them. I have a ford 9" rear end open housing, large tube and a 31 spline trac loc with 3.25 gears for it. I want another trac loc or detroit locker center section with either 3.89 or 4.11 gears for it.

Now, can someone explain what to look for in buying a center section for a 400+ hp car. What makes one more $$$ than another? I've seen N case, war case, no name case, aluminum strange case, and truck case.

Thanks,
 

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First off, you'd likely need way more than 400 HP to break any 9", with the possible exception of the WAR case. The WAR case is still plenty sturdy, but I'd be a little leary of running one behind that much power. I have a WAR case, though, behind the 289 in my '66 (probably 300 HP at the flywheel) and it's seen well over 30 passes at the track and 50k street miles.

I just have the "plain" case behind the 408 in my '69, but I am using 31 spline axles.

The strongest of them all are the "N" cases (higher Nodular content), but they are also the most expensive.
 

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Yep, I remember seeing a sight once that sold ring and pinion gears from about 6 different manufacturers. They had them rated for strength, longevity, and a few other things. Actually was a pretty nice site. Basically it seemed like the biggest difference was the hardness of the gears. Hardest=longest wear, but tend to be on the brittle side. Softest=Take the biggest beating without breaking, but don't last as long.
 

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The WAR case is actualy weaker than the standard single web truck case. I have a WAR case in my 65 but it will never see slicks and even if it did I will break a drive shaft and or axle before the case. The pinion support would be my first choice in upgrading a standard case and from there I would go with an after market case.

As explained already softer gears are used for all out drag cars and if you run them on the street you will need to have the back lash set more than one would like to do.

It all boils down to what you waht to do with the gear set? On any rebuilt third member I would always suggest installing a solid crush sleeve. Controling the pinion movement is always a good thing! When it moves, teeth like to break!
 

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If your not on a strict budget and want to leave room for future horsepower increases go with the Currie 9+ Nodular case. Make sure you also get a strong pinion support ex. Daytona big bearing.
 

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There are actually two other variants of the WAR case that are as equally weak, due to their gray-iron casting. The other two are the; WAA and WAB cases.

The (commonly seen) single vertical rib 9-inch 3rd member case is a very strong unit, because it has some nodularity in its casting, but the ultimate 9-inch case is the N-case which has a very high nodular iron content that allows it to flex, rather than shatter like the old WAA, WAB or WAR 3rd member cases.

http://ultrastang.com/Rearinfo.asp?Page_ID=9
 

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Make sure you also get a strong pinion support ex. Daytona big bearing.
Pic of rear in my '66 from local r&p shop .


 

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It appears to be a 4 pinion trac loc which is the better of the trac locs. The case appears to be a standard case. Ask for the casting number, C7?
 

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Ok then, what type of case was used in the 70 mustang 9" rears?

Also, not to hijack but what all is involved in upgrading to the daytona pinion support? I have a rear rebuild in my near future, as my car has anal seepage :lol:
 

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That case would be the one used in the 70 stang. It more than likely has the C7 casting number on it. The upgraded pinion is a matter of buying the new pinion support and bearings and you should also install a solid crush sleeve in the new pinion support.

I've seen the pinions break from 4x4 abuse and very large sticky tires but I have also seen the trac cover split in two from the same abuse described above. Point is using a factory trac loc may not require the use of the upgraded pinion support but it couldn't hurt. if you're really going to run it hard then you need to figure out where to draw the line as far as upgrading the 9 inch components.
 

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Are you looking for a period correct case? I can't recall the WAb numbers off the top off my head and I won't be home tonight until 10 or so from work.
 

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a quick search of ultrastangs site reveals the WAA and the WAB are the same case as the WAR case and are the weaker cases of all the 9 inch cases which was manufactured until 1960. if this is true then no it would not be in your car.
 

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The case pictured appears to be the C7AW 9-inch case. This is a good one to have short of an N-case.

The differential is a Ford 4-pinion Traction-lok unit.
 
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