Pic of 8" carnage; advice on 9" needed.

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Jul 23, 2005
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Who doesn't like looking at pix of broken parts? Here ya go:

176116.jpg


What you are looking at is a Richmond Gear 3.55:1 ring and pinion, with the ring gear missing a tooth, and an Auburn clutch-style lsd, in what's left of a 43-year old 8" carrier. This happened the third time I ever tried to do a burnout since I put Slide-A-Links on my '65. I guess the Slide-A-Links work. Sitting at a stop sign, I wound it up to about 2000 and popped the clutch and BANG! You'd think I was running Chevy parts!

So now I'm thinking to go to a 9". At the high end is an all-new Currie housing and pig, a Truetrac torsen diff, 31-spline axles, and the Explorer disc brakes, at $2800. It's $330 less with a used Ford pig. At the low end would be to replace my broken pig and 8" ring gear.

Advice, please! What to do next; sources; prices; etc.

Also, what ring and pinion gear should I run? This car has a T5 from a '96 Mustang GT. I had a 3.55:1 and it seemed low enough to me, but it seems like the Mustang 5.0 guys with T5's usually switched to a 3.73.
 
how about an 8.8

It would be a bit costly to upgrade your 8" back. With an aftermarket carrier and a new ring gear, you might as well invest the money in something else. I plan on upgrading junkyard style with an 8.8 out of an 86-93 mustang with 5 ug axles from the ranger/aerostar bin, and regular drum brakes. However, this axle is wider, but i will be running 05+ wheels so no prob there. The biggest source of cost for this mod is to get the spring perches welded on, and maybe a set of c clip eliminators.

Fox body guys like to run 3.73 gears so they can use 5th gear in the city for putting around. Depends on how much highway driving you really except to do. I don't know quite what rpm it would be, but I do know that 1st gear goes by quick :lol: also it makes across town commutes much easier with a faster gear, and less load on teh trans
 
With the low 1st in your T-5, I'd stick with 3.55 (8") or 3.50s in a 9". I run 3.70s, but with t 2.95 1st gear. I think your 1st is 3.35, so you don't need as much gear in the rear. I went with the Currie 9: you describe. It is pricey, but it comes complete. Just bend new brake lines to fit and slap it in.

The option is to get a 67-up center section, which is a little stronger than the 65-66 centers. Your choice.
 
I am a member of the 8.8 club, so I may be a little biased. I have about $300 plus sweat equity in mine. It is a 95 GT readend. I can not imagine the Currie is almost 10x better. I would think you could do a nice 8.8 for about half that with custom 31spl axles with 9" ends and gears of your choice. They leave a little more power for the tires too.
 
I would consider the 8.8 route, but when you throw slicks on it, your back in a tough spot. 8.8's dont handle high rpm/slick launches very well. A 9 inch will be nearly indestrcutable. So 8.8 with forged axles and after market dif., vs 9 inch rear maybe?
 
I know a guy that went 5.90's in a 93 Mustang with the 8.8 being bone stock except the gears. I am not saying it was smart, but it did happen. He had about 40 passes on it when he finally upgraded it. It has a 408 with a bottle and a C4 with a brake. Go look under cars at an NMRA event. You will see more 8.8's in 8 and 9 second cars than you would think.
 
So now I'm thinking to go to a 9". At the high end is an all-new Currie housing and pig, a Truetrac torsen diff, 31-spline axles, and the Explorer disc brakes, at $2800. It's $330 less with a used Ford pig. At the low end would be to replace my broken pig and 8" ring gear.

Advice, please! What to do next; sources; prices; etc.

Also, what ring and pinion gear should I run? This car has a T5 from a '96 Mustang GT. I had a 3.55:1 and it seemed low enough to me, but it seems like the Mustang 5.0 guys with T5's usually switched to a 3.73.

You'll probably never have to worry about a 9" in a light car like '65, even a 28 spline. I wouldn't buy from Currie, though. Their prices are way too high IMO. If you want to do it yourself, there are a few guides floating around on this site.

The Fox3 crowd likes 3.73s because they don't mind turning 2800rpm at 60mph. 3.50s won't drop that down too much, but I think they are a good choice for sub-3000lb cars like yours. If you do much 55mph+ driving, you might even consider 3.25s.
 
Do like Ford/Shelby did in 65/66...
Cut the pumpkin portion out of your 8" housing and replace it with a 9".
Then install a chunk with 28 spline carrier.
Done.

This way you just use a 9" donor that is cheap/free, instead of looking for a bolt-in specific part that will co$t.

Dave
 
Sure, rub it in guys. Actually, my old man needs a 9" for a '51 Ford pickup he just got. The Dana-whatever that's in it is pretty far gone. I'm not sure what width it is, though.

As far as prices(to keep this on topic for mrmustang):EDIT: that I paid:
- '57 passenger car housing with junk axles, junk brakes, and no center section; $150 shipped.
- '57 axles and brake drums; borrowed.
- '70s big car 28spl T-lok with 3.50s; $350 shipped.
- bearings, seals, shoes, and wheel cylinders; $100.
- U-joints and trans yolk, $100. (I recommend Spicer u-joints, not the off-brand garbage I got).
 
I would spend a few minutes on the phone with Currie. they built a new 8 inch for us (AdamInChains)., but instead of using the original mustang center section, they recommended using a different ford casting that has additional webbing and most importantly a beefier pinion bearing support. They told us that this set up was used commonly on sprint cars. We were going with 3.55 gears and a Eaton true trac. the added cost was ~ $20. How much HP/torque were you putting on the groud?
 
Thanks for all the replies.

To mrmustangman357, brianj5600, and BullittStangV8, et al.: I will search the forum for "8.8" and see what I find. Is there any vendor who offers a drop-in kit for a '65? I'm in automotive Siberia -- Berkeley California -- and I seriously doubt I can find anyone to weld on the spring brackets.

Anyone in the SF Area know of someone to do this job?

My current oil burning 289 was popping about 150 hp, 200 ft lbs at the flywheel. I am putting in a rebuilt 302 with roller cam and Ford iron heads this summer, which will be a big improvement but nothing extreme.

At the same time, someday I'd like to put in a 427 Clevor or a turbo 331, keeping it stick shift. So there is that much of a reason to go for the gold.

SoCalCruising: I think I'll stick with the 3.50 or 3.55 gears. I like the ease of the Currie option too. But jeeze, sales tax alone on a 2800 package is $250. Shipping too. I only paid $2500 for the whole stinkin car five years ago.

D.Hearne: are you serious, $50 plus shipping? If so, you're on (if your email inbox isn't already clogged with other takers).

truck90278: I will call Currie and ask about the 8" chunk option. One thing I am really strong on (but not carved in stone) is the torsen ("True Trac") differential.

I hope I covered all the responses. I really appreciate the input. This is a great forum.