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30 or 33 spline?

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Old Dec 2, 2004 | 10:41 AM
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Default 30 or 33 spline?

Someone please help me understand this. I am ordering my 12 bolt tomorrow, and some people say to just stick with a 30 spline, others say to upgrade. What are the actual benefits of upgrading? I plan on doing a cam in the spring, and there is a chance of doing heads later. What do I get? Will the 30 spline hold?
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Old Dec 2, 2004 | 09:45 PM
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let's see if i can help.......

the only down side to bigger axles is a little bit more weight. so what! if you have the extra cash, get no less than 35 spline axles. first of all, they're stronger, no question. second, if you ever need to sell the rear, it will be much easier to do so with bigger ones. also, if you even have the slightest thought of going much faster, you wont have to think about upgrading later and spending extra dough. and if you can afford to go a little bigger yet, get the 9". you wont regret it for the same reasons i mentioned about going with bigger axles. hope that helps.

Dave

ps-if you only do a minor setup with heads and cam and maybe a 100 shot, just do a 12 bolt with 33 spline if you can't afford 35's. not a big deal, so don't worry about it.
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Old Dec 2, 2004 | 10:22 PM
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33 spline. Strange comes standard with them now. Your posi choices are limited but you will be fine since eaton makes the posi in 33 spline configuration
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Old Dec 4, 2004 | 10:59 AM
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i was quoted only $100 more for a 33 spline.



this is for a moser.
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Old Dec 4, 2004 | 11:22 AM
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Has anyone broken a 30 spline axle?
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Old Dec 4, 2004 | 11:38 AM
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Just go 33 spline.........
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Old Dec 4, 2004 | 11:41 AM
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Originally Posted by Mooobunnny
Just go 33 spline.........
I understand that its bigger, but I was wondering if its worth the extra money when nobody ever breaks a 30?
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Old Dec 4, 2004 | 08:29 PM
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Since your on the eastern section, IIRC Noyzee twisted his 30 splines. Granted he was running a twin turbo setup at the time. I believe the 33 splines are warranteed, but I don't think the 30s are. For an extra 100 bucks, ya can't go wrong.
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Old Dec 4, 2004 | 09:03 PM
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What are your ultimate plans with the car? What kind of differential are you going to run. If its just heads and a cam 30 should be fine (as long as its not a spool). You may want to consider 33 spline just for the insurance/peace of mind. I personally run gun drilled 35 splines mainly cause I drive a spool on the street.
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Old Dec 4, 2004 | 09:09 PM
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Originally Posted by PRAY HRD
ps-if you only do a minor setup with heads and cam and maybe a 100 shot, just do a 12 bolt with 33 spline if you can't afford 35's. not a big deal, so don't worry about it.
The 35 spline is an option for 9", the 12 bolt is 30 or 33. The only thing that is stronger with the larger spline is the axle itself. If you are over 400 rwhp, I would spend the extra cash. The weak link is usualy the diff case/ carrier assembly, and the larger spline doesnt help that. Some guys will twist the smaller shafts, but I usually see more broken cases.
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Old Dec 5, 2004 | 12:23 AM
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mzoomora.......... you're right. been a while since i even looked into a 12 bolt since i went with a 9". therefor..........go with the 33 spline.

Dave
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Old Dec 6, 2004 | 08:21 AM
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I am planning a cam in the car, and then its time to focus on paying it off and getting a Vette.
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Old Dec 10, 2004 | 01:56 PM
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I understand everyones mentality about bigger is better. But it all depends on your application and how often do you put a gummy tire on the back of the car and drive it like you stole it. For a street warrior with occassional trips to the track 30 spline is more then enough. I bought a Auburn posi (31 spline)for a 10 bolt rear in Bowling Green off this guy in vendours row. This was the Buick GN shootout they have every year. I bought all my pieces to complete my 10 bolt in my GN. I went to install it and found out that it was a 12 bolt instead of a 10bolt. But I ordered a Eaton 30spline 10 bolt carrier for it and had everything installed. The 30 spline was good enough for me. I run high nines to low 10's with a 1.38 sixty foot off the transbrake in a 3500 pound car without me in it. I have had over 50 hard passes on this rear end since with no issues. Bigger is better don't get me wrong. But it is not nessessary on a 10 sec car. The weak link in most cases is not the center section, its the thickness of the axle tubes with the torque pushing them around. I also have the Wolfe racecraft single sway bar to make it launch even and the LPW rear cover with the axle braces on it to stop the the majority of the movement along with welding the axles tubes. So the way I see it, is if a 10bolt will hold my duty then a 12 bolt is that much stronger. 31 spline is more then enough unless your building something that makes huge amounts of power.
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Old Dec 13, 2004 | 05:24 PM
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i blew 2 10 bolts, bent 3 30 splins, blew my 12 bolt to junk, 6 cluches and 3 tranny's befor i decided to go 33 spline, spool, and auto, now i just blow drive shafts. hehe. you cant win
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