9'' or 12 bolt?
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TECH Resident
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From: East Los Angeles CA
9'' or 12 bolt? im getting an ls1 swap on my 67 camaro and im now about to make my choice on either the 9'' or 12 bolt rear end...i had got a quote for the 9'' but i heard from a friend of mine that since the 9'' is soo much more heavy it should take more power to push the gears on that strong *** rear end...is this true....will i loose 30-50rwhp if i get the 9 inch or should i just go with a 12 bolt...i mean im only going to be pushing around 400 hp....any help will be great
Here's a little food for thought.
There is no question the 9 inch is a stronger rear end. But at your horsepower level you don't need it. I run a Strange 12 bolt and a TH400 and at the LTx shootout I ran 13.0s at 103. Bolt on LT1 that with a 60E and stock 10 bolt rear ran 13.4 at 103. No change in trap speed, know what that means? No power loss whatsoever with the TH400 and the 12 bolt. Now I did change to a 4k stall and 4.10 gears instead of 3.73s and the ability to 60 foot better (1.75) is what shaved 4 tenths off my ET.
In my opinion get the 12 bolt, plenty strong enough and won,t rob any horsepower.
There is no question the 9 inch is a stronger rear end. But at your horsepower level you don't need it. I run a Strange 12 bolt and a TH400 and at the LTx shootout I ran 13.0s at 103. Bolt on LT1 that with a 60E and stock 10 bolt rear ran 13.4 at 103. No change in trap speed, know what that means? No power loss whatsoever with the TH400 and the 12 bolt. Now I did change to a 4k stall and 4.10 gears instead of 3.73s and the ability to 60 foot better (1.75) is what shaved 4 tenths off my ET.
In my opinion get the 12 bolt, plenty strong enough and won,t rob any horsepower.
I really doubt you would notice an et difference between the 12 bolt and the nine inch, but the 12 bolt will work just fine with your leaf springs. I don't recommend a 12 bolt on the late model f body's, as the torque arm mount seems to cause the housing to flex. Bob
Go with the 12. It is very true that the 8 inch will take your power. I know a guy who was running 9 flats with a 12 and "upgraded" to a 9" only to lose two tenths of a second in the quarter. It's the same principle with a turbo 350 and a turbo 400 trans. The 400 is stronger but it takes 12 more horespower to run it. If you can use the smaller one that takes less power w/o any problems (which you can) the go with that
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TECH Resident
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From: Omahaish. Nebraska.
Wouldn't you be able to weld the axle tubes together on the 12 bolt to help with strength? If that's possible, I don't see why the 12 bolt can't take the same, if not more abuse than a 9 inch.
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Here is my link to where I sell the Moser 9 inch rear that bolts right into our cars. Bob