12 Bold Chevy & Dana 60 Rear

[V10nacuda]

Just curious on the reliability of a 12 Bolt chevy in a heavy car like SS/EA or similar weights running 9.50's to 9.0's. I bought a mopar with a 12 bolt that has good parts that ran in EA. The car is now getting a B1 Motor with about 850hp. I am wondering if the 12 bolt will be an issue. I'm guessing that the car without any weight bars will weigh AT LEAST 3500# with me in it.

I know some of you SS guys use the 12 bolt over the Dana or 9in to save weight & parasitic loss.

Looking for some input.

Thanks

V10

[Jim Wahl]

Jim Kinnett used a Chevy 12 bolt in his 68' Cuda Pro Stocker for several years with success.With the availability of even more modern, better quality parts I would think it would hold up fine. Jim

[Myron Piatek]

Originally Posted by Jim Wahl

Jim Kinnett used a Chevy 12 bolt in his 68' Cuda Pro Stocker for several years with success.Jim

Wasn't that an SS/AA Cuda before he got into Pro Stock?

[Geerhead55]

Yes,,,Jim's Cuda was a SS/AA in the old days with a 12 bolt. There are plenty of shots of the car in old Super Stock and Drag Illustrated magazines. We thought it was wierd at the time, but he claimed the 12 bolt was lighter and more efficient than a Dana 60 or a 9 in. Danny Durham

[John Leichtamer Jr]

Use the Moser Housing 12 bolt. A quality rear end Casting alot heavier.

Hammer

[V10nacuda]

THanks for the input. I think I will add a cast girdle cover & try it out. The car has 5.13's in it now so I'll try some 1/8 mile hits to see if it holds up. If it stays togeather I'll probably swap for the 4.56 Pro gear. (foot braking).

Thanks
V10

[Marine One]

I was always under the impression that the larger the ring gear, the "easier" it is to turn, thus the larger ring gear rears are more efficient. Kind of like the rear sprokets on a 10 speed bike. When the chain is on the smallest sproket it takes more muscle to pedal. When it is on the largest sproket it takes much less effort to make the wheel spin.

On the other side of the token, guys were pulling their super heavy Dana's out of Cuda's and replacing them with lighter 8.75's and going faster. Not becase of rear end efficiency - because of total weight savings.

[Mike Taylor 3601]

The weak spot on 12 bolt or dana 60 is pinion not having support at rear of pinion like 9'' does. What happens is pinion head will bend and develop run out,tight one side turn pinion half turn will be loose(backlash) You can put any housing,rear cover etc.you want but it will not stop pinion from bending.
I ran 2900 lbs 5 spd car @6 teens 1/8 w/1.26 60' about 35 runs was life of gears and that was with soft properly setup clutch wrong clutch cut that life in half. It was 12 Blt. all mark williams parts billet caps and all.
Mike Taylor 3601

[V10nacuda]

Originally Posted by Mike Taylor 3601

The weak spot on 12 bolt or dana 60 is pinion not having support at rear of pinion like 9'' does. What happens is pinion head will bend and develop run out,tight one side turn pinion half turn will be loose(backlash) You can put any housing,rear cover etc.you want but it will not stop pinion from bending.
I ran 2900 lbs 5 spd car @6 teens 1/8 w/1.26 60' about 35 runs was life of gears and that was with soft properly setup clutch wrong clutch cut that life in half. It was 12 Blt. all mark williams parts billet caps and all.
Mike Taylor 3601

Interesting....I.m guessing that was with a PRO gear????? WHat were the symptoms when they started to go away????

V10

[Mike Taylor 3601]

Yeah Pro gears if caught it in time pushing car would get hard then easy then hard,best way to keep track was check play at pinion by drive shaft see if felt the same several
spots if did'nt catch it wiped practically every tooth of pinion and about half ring gear when
it went.
Mike Taylor3601