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Discussion Starter · #1 ·
I posted this on the tech forum and got one response. I need more to go on guys please help.
I learn alot about these things just from hearing the talk; 9" rearend with large bearing ends, daytona pinion, and 31 spline axles. What I need to know is just how much of this is really good to have and what is just extra? In my case a lot of extra time/money. My application will be in an FE powered 65 galaxie that will be brought to approx 450 HP and raced occasionally for fun, otherwise street driven. It has the stock 65 9" with the dimples in the back (not the usual hump), small bearing ends, and I'm sure 28 spline axles. I read that the 67 and up housings are stronger. Again, how much concern do I need to put to these details? I've already read the tech article on this forum, but need more info. I have retreived a C7AE 9" with the large bearing ends that I'm thinking of rebuilding, but it will need some work and fabrication to get it compatable with my 65 Gal. Just want to know if its worth the extra effort.

 

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automatic?..........slicks or just wide sticky's.........ratio.......track bars?
 

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The only difference in the 67 rear end is where the springs go on,a 65 wagon rear will have the big bearings and will bolt in without any modifications to where the spings attach. A local junkyard here in the Dayton Ohio are has a 65 wagon. Jeff
 

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I've heard it's just the 65 and newer that were stronger, and really no difference between 65 and 67. I have a 64, first gen 9" and needed a brace welded on the housing for strength. I'm also runnin' about 650 hp, so I've upgraded moreso, ex. 35 spline axles. For 450 hp's, going 31 would be good, but 28 may do. Really, the typical will work fine until you push lots of power, and even still I've heard of people running 600-700 hp with 31 spline and daytona pinion etc. so???
 

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There are a bunch og variables that factor into how far you can take any differential. IMO - a 450HP motor through a small stall converter and street trans on street tires should be fine through a stock 9". 450 HP behind a hard shifting race tranny with a brake and a 4500 RPM converter and slicks in a 4000lb car is trouble. The issue is really less about the HP tha the car is making and more about the kinds of shock loads that the drivetrain/car is putting on the diff. I have seen two 9" diffs break and they were both big inch N20 engines launching heavy cars on slicks at the track. One snapped axles and the other blew the pumpkin out of the front of the case - the guy had rebuilt with good internals and not replaced the studs between the carrier and the housing . I have seen dead stock 9" diffs take a bunch of abuse on the street and not die.

My car's previous owner used to launch it on the bottle with a 150 hp shot on top of a mildly warmed over 352 (cam intake, headers, etc...) @ well over 4000 lbs and the diff was fine when I pulled it apart this year to put in new gears. This was a dead stock '65 9" - no datona pinion, large bearings etc....
 

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Leaf spring axles housings are weaker then a control armed axle housing.


Shadow, Your 9" will be FINE. Your only weak point is the 28 spine axles/diff and that depends on factors that others have mentioned in this thread.



_________________
1965 Galaxie Fastback-351C 2v/C4 with a 3.50 posi

1973 Gran Torino Sport (sold)

2004 Cobra
2004 Marauder

<font size=-1>[ This Message was edited by: wildosvt01 on 4/25/06 4:26am ]</font>
 

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Discussion Starter · #8 ·
Well I figure it didnt hurt to get the whole housing out of that donar cougar before it went to the scrapyard. The gears in it are fried, but there is always the large bearing end housing I'm sure I could use for something, plus, I haven't measured, but I think the drums are wider and larger in diameter than my stock drums in the rear. Im assuming they will bolt right on RIGHT???
 
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