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.