GM Stocker rear end choice

RJ · 01-25-2009, 05:29 AM

Which GM rear end would be quickest yet be durable enough for an automatic stocker weighing 3900 lbs. and running 10.80's? - gears would need to be available in the 5.13 - 5.57 range.

Thanks

Dragsinger · 01-25-2009, 07:55 AM

R J,

what power - performance range are you expecting?

Alan Roehrich · 01-25-2009, 09:25 AM

RJ, there are some guys running the 8.5 late model 10 bolt in real fast cars. I'm not completely convinced that the reduced weight and drag is enough to offset the increased risk of breakage and the increased maintenance costs. It's the same basic design as the 12 bolt, it is just slightly smaller and lighter. I'd say you could get by with doing it. I'm not sure it'll make enough difference in ET and MPH to cover the at least 50% reduction in ring and pinion life, especially when you go to 5 series gears, as the pinion gear gets really small, and that's where the weak point is.

Rich Biebel · 01-25-2009, 11:01 AM

With a weight of 3900lbs and a predicted ET range of 10.80's, I have to assume this is a bigger cube engine. It takes a lot of power to run 10.80's at that weight. I would not race that with anything smaller than a 12 bolt if it was a GM vehicle. Breaking rear ends is not fun.....

RJ · 01-25-2009, 11:10 AM

Yes, in asking around I'm getting the same answer, 12 bolt it is, thanks all.

Greg Reimer 7376 · 01-25-2009, 11:30 AM

Just for curiosity's sake,what are you thinking of building that weighs 3900 pounds and goes 10.80's? A 427 Caprice or something? Yes, a 12 bolt is the right choice.

Robert Swartz · 01-25-2009, 12:03 PM

Quote:

Originally Posted by RJ

Which GM rear end would be quickest yet be durable enough for an automatic stocker weighing 3900 lbs. and running 10.80's? - gears would need to be available in the 5.13 - 5.57 range.

Thanks

With this heavy a car, 12 bolt, no question.

I'm preparing to build a 34-3500 pound crate motor car and we're going to utilise a 10 bolt. I still have my concerns but after a few consultations. I am less afraid of these rear ends on a lower HP footbrake stock class car.

If I were building a high torque engine, that would be launched by either a stick or a trans brake, if I were limited to or desired a GM rear, a 12 bolt would be the only choice.

danny waters sr · 01-27-2009, 11:04 PM

R J , You got mail !!

Jim Kaekel · 01-28-2009, 11:47 AM

RJ: Definitely go with the 12-bolt, and with a "pro" 9310 steel gear. You will definitely break the teeth off of the gears with that much power and weight if you use a "street" 8620 steel gear. I have an Olds that I've run for quite some time, weighs around 3800 lbs. and has run a best of 10.85. Add to the fact that nobody offers a "pro" type gear for the GM 10-bolt that I am aware of.

01-25-2009, 05:29 AM	#1
RJ Member Join Date: Oct 2002 Posts: 248 Likes: 0 Liked 0 Times in 0 Posts	GM Stocker rear end choice Which GM rear end would be quickest yet be durable enough for an automatic stocker weighing 3900 lbs. and running 10.80's? - gears would need to be available in the 5.13 - 5.57 range. Thanks

01-25-2009, 07:55 AM	#2
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: GM Stocker rear end choice R J, what power - performance range are you expecting? __________________ Larry Woodfin 471W

01-25-2009, 09:25 AM	#3
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,116 Likes: 1,573 Liked 1,832 Times in 415 Posts	Re: GM Stocker rear end choice RJ, there are some guys running the 8.5 late model 10 bolt in real fast cars. I'm not completely convinced that the reduced weight and drag is enough to offset the increased risk of breakage and the increased maintenance costs. It's the same basic design as the 12 bolt, it is just slightly smaller and lighter. I'd say you could get by with doing it. I'm not sure it'll make enough difference in ET and MPH to cover the at least 50% reduction in ring and pinion life, especially when you go to 5 series gears, as the pinion gear gets really small, and that's where the weak point is. __________________ Alan Roehrich 212A G/S

01-25-2009, 11:01 AM	#4
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,314 Likes: 25 Liked 544 Times in 213 Posts	Re: GM Stocker rear end choice With a weight of 3900lbs and a predicted ET range of 10.80's, I have to assume this is a bigger cube engine. It takes a lot of power to run 10.80's at that weight. I would not race that with anything smaller than a 12 bolt if it was a GM vehicle. Breaking rear ends is not fun..... __________________ Rich Biebel S/C 1479 Stock 147R

01-25-2009, 11:10 AM	#5
RJ Member Join Date: Oct 2002 Posts: 248 Likes: 0 Liked 0 Times in 0 Posts	Re: GM Stocker rear end choice Yes, in asking around I'm getting the same answer, 12 bolt it is, thanks all.

01-25-2009, 11:30 AM	#6
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,136 Likes: 172 Liked 705 Times in 219 Posts	Re: GM Stocker rear end choice Just for curiosity's sake,what are you thinking of building that weighs 3900 pounds and goes 10.80's? A 427 Caprice or something? Yes, a 12 bolt is the right choice.

01-27-2009, 11:04 PM	#8
danny waters sr VIP Member Join Date: Apr 2007 Location: lagrange,nc Posts: 2,224 Likes: 1 Liked 0 Times in 0 Posts	Re: GM Stocker rear end choice R J , You got mail !! __________________ Danny Waters, Sr / 73 Duster "340"

01-28-2009, 11:47 AM	#9
Jim Kaekel VIP Member Join Date: Jul 2002 Location: Michigan Posts: 1,229 Likes: 133 Liked 535 Times in 110 Posts	Re: GM Stocker rear end choice RJ: Definitely go with the 12-bolt, and with a "pro" 9310 steel gear. You will definitely break the teeth off of the gears with that much power and weight if you use a "street" 8620 steel gear. I have an Olds that I've run for quite some time, weighs around 3800 lbs. and has run a best of 10.85. Add to the fact that nobody offers a "pro" type gear for the GM 10-bolt that I am aware of. __________________ Jim Kaekel 3836 STK