12 bolt gear set treatment options
 

Racers,

with my Super 10 buildup it uses a 6.0 ratio 12 bolt. The truck will run low 10's at about 3100 pounds.

It has a 327/300/293 with powerglide and I will leave with trans brake.

My experience with a 12 bolt in other race cars is good, all giving excellent service life. However, never anything lower than a 5.13 ratio.

The pinion for a 6.0 ratio is mighty small, each time it look at it I shake my head.

Let me hear about your experience with gear treatment options

Re: 12 bolt gear set treatment options
 

Why not use a 9" Ford?

Re: 12 bolt gear set treatment options
 

Ed, the 12 bolt housing is narrowed, braced, all brackets installed, Strange axles in house, spool and all hardware in house, under the Super 10 and ready for gear set.

At this time it is reasonable to move forward with the 12 bolt. I am willing to test the life span of the 12 bolt.

You can see photos of all the above in my Super 10 buildup.

Re: 12 bolt gear set treatment options
 

I don't get out much anymore, I guess.
I've never heard of a 6.00 12 bolt.
I thought it was 5.86, then 6.14.
Who makes the 6.00 ?

Re: 12 bolt gear set treatment options
 

Mark,

US Gear sold by Strange.

Re: 12 bolt gear set treatment options
 

Larry,

I have a friend that races a GTCA Camaro with a 12 bolt. I think he has a 5.87 ratio. He gets between 100 and 150 runs on a ring and pinion. I would expect you will get similar gear life from your combo. I have a Dana 60 in my car with 5.86/6.17 ratio and I get several thousand runs on the ring and pinion in my car. The 12 bolt is not real strong but will be fast. I think its LPW that makes a girdle cover with a strut rod that runs to the end of each axle tube. This would be a good choice for your Truck. Also some billet caps.

Re: 12 bolt gear set treatment options
 

I haven't sat down and counted the runs, but my Chrysler 8 3/4 gears have been lasting longer with cryo and REM surface finish treatments. I've had them done at Evans Performance near Atlanta.

http://www.evansperformance.com/

There was an article years ago showing that a 12 bolt was the most efficient differential. A Dana 60 is more efficient than an 8 3/4" which helps compensate for the weight and a Ford 9" is one of, if not the worst for efficiency.The pinion to ring gear relationship has a lot to do with the efficiency ratings.

Re: 12 bolt gear set treatment options
 

Mike,

LPW cover on hand. Strange replacement caps installed. Custom, in house housing bracing already completed. {all these items shown in my buildup post :) }

Re: 12 bolt gear set treatment options
 

Myron,

Thank you, that is the info I needed. I appreciate the note.

Re: 12 bolt gear set treatment options
 

As to what Myron said, I two remember reading that article about horse power loss using the different rearends. And about that same time someone with an SS/BA Hemi Cuda was using an 12 bolt for that very reason without issues. BTW, I'm enjoying S10 build.

Re: 12 bolt gear set treatment options
 

You are all over it Larry. I have been watching the build. Cant wait to see the finished product. Keep up the good work. Thanks for posting the progress.

Re: 12 bolt gear set treatment options
 

Jim Kinnett was running a 12 bolt Chevy rear end in his Super Stock Hemi 'Cuda, probably 2-3 decades ago. I'm thinking they were replacing the ring and pinion at 50 passes or so. They were not getting great life out of them. They were taking advantage of the efficiency and the lower unsprung weight, but were saying that came at a cost.

Re: 12 bolt gear set treatment options
 

I have pulled out a couple of cracked 5.57s with one season on them, and knocked several teeth off one at either Gilliam LA or Ennis (forget which), on the starting line, last year. That low of a gear (6.0) would make me very nervous. Mine has to weigh 3235. I have had a couple of people tell me mine hits the tires too hard. Not sure what to do about it. Feels OK in the car.

Re: 12 bolt gear set treatment options
 

Although Strange Engineering makes a 12-Bolt Drop Out 9" Center Section, they only recommend its use on very lightweight cars like dragsters and altered cars.

Re: 12 bolt gear set treatment options
 

Kenny Faulk told me once he had one in Amy's Firebird Stocker. Don't know if he still uses them.

Re: 12 bolt gear set treatment options
 

Outside of factory race cars, a 9" Ford housing in a GM car isn't really legal, even if the center section accepts a 12 bolt ring and pinion, and you can't run an aluminum center section in a car that didn't have it as an OE component.

Re: 12 bolt gear set treatment options
 

Put a 12 bolt in my car in 87 283 220 hp glide with a brake 3200 +, 6.14 high 1.40s 60s. Raced hard for 10 years, brackets, combos, div, and natl events. All with the same set of gears, thousands of runs, lucky maybe. Made sure from the start with steel caps, rear cover girdle and made sure the set up was dead on. Put the second set in ran them till 09 when semi retired. Working on a new housing for the car, will try the 6.00 ratio with rem finished and cyro but like everything else today the stuff is just not made the same. Good luck on the build, looks great and have fun. Only rear that has less drag from gear angle is a dana 60 but they are heavy [un sprung weight]. Tom

Re: 12 bolt gear set treatment options
 

Tom,

Thanks for the note. As suggested by you and Myron I am sending the gear set to Evans Performance in Georgia. They will do Cyro and REM treatments.

Re: 12 bolt gear set treatment options
 

So, all these SS cars with 9" rears are illegal? (He isn't building a Stocker.) Boy, I have one of the few legal SS cars around here. LOL

Re: 12 bolt gear set treatment options
 

Larry,
My differential guy set the gears up before I sent them out because he said if you choose the "shiney" REM treatment, it's difficult to get a clear pattern. Unfortunately, you don't have the option of a drop-out center section.

Re: 12 bolt gear set treatment options
 

Myron.

good idea and sounds reasonable. I can do that because the pinion is already in the housing with an estimated setup shim pack. I was just going down to take the pinion out and box up for shipping so your note came just in time.

Thanks

Re: 12 bolt gear set treatment options
 

Alan,

building a super stocker, any housing is legal

Re: 12 bolt gear set treatment options
 

We tried everything to get a 5.86 and 6.00 gear to live in our car....350 cu in. 993/997 with 615 estimated and around 510 torque... Mark Williams Caps, LPW Cover, Shockproof Red Line Oil.. ( Still have 5 gallon never opened). Set them up Tight...Loose...Deep...Shallow...Took the housing out and had it completely updated with additional bracing @ PK Racecars....
Never made any difference..@ 25 runs it was making noise...And @ 50 they were gone.You might run them close to a hundred, but you were holding your breath.. I think the weight is very crucial. We were @ 3300. We changed classes and went to a 3000 pound and a 5.57 gear and never had any problems . Can run this set up year after year...Those little pinions don't like weight,

Re: 12 bolt gear set treatment options
 

Ed, you didn't read all of that. YOU were talking about a stocker in the post I quoted. I was not talking about Larry's project at all. Our SS/EA 69 Camaro has a Dana 60, I know rear ends from other manufacturers are legal in Super Stock.

Re: 12 bolt gear set treatment options
 

Sorry Alan.

Re: 12 bolt gear set treatment options
 

I have the 6.0 ratio setup completed and have removed the ring and pinion to be sent for treating. At the suggestion of Myron I shipped the gears here

http://www.procryo.com/index.html

for REM and CRYO processing

Re: 12 bolt gear set treatment options
 

I' m planning a 8 3/4 build and was going to cyro and rem the ring and pinion. I know the rem in mirror polishing. Just curious if anyone has gone the anealon treatment (ceramic coating) as apposed to rem finishing? Same for bearings ceramic or anealon coatings. Thanks, Rick