rear axle advice
 

Long time follower on here but i've finally started on my 67.. I'll be running a 5.3/4l80e single turbo, mostly street but definitely will hit the track. I plan on running 4.11's with a posi in the 12 bolt with drag radials. I want to do a c-clip eliminator but saw elsewhere on here that it isn't great on the street? (not sure why). Are the axle shafts ok up to 600ish hp? Do you recommend welding the tubes to the housing? Thanks!

Re: rear axle advice
 

Welding the tubes is cheap insurance. I'm running the stock spline count but the axles are Moser. I haven't had any issues and well over 600hp.

Re: rear axle advice
 

With that much hp/tq I would go with aftermarket axles. Of course the durability of the stock axles will be relative to the size and rubber compound of the rear tires you run. If you do go with aftermarket axles, you may as well narrow the housing a little to accommodate a wider tire and also weld on the correct Moser #7950 housing ends.

Re: rear axle advice
 

Call a reputable company, Currie, moser and talk to their tech.

Re: rear axle advice
 

Ok thanks guys

Re: rear axle advice
 

Since you're going turbo, use a higher gear ratio to load the engine and get into boost. 3.08, 3.23, 3.42, etc. I've got a 3.25 in my 9" and it works great. 1.62 60' on the footbrake at 4150lbs.

Re: rear axle advice
 

^^^
THIS - don't even mess with C-clip eliminators. Use the Ford Housing ends with GM bolt pattern - that is the correct Moser #, and then get axles from them too. I speak from experience here. I welded my tubes to the housing, narrowed the rear 2", used the Moser 7950 ends and Moser axles with a Moser diff cover/girdle with a Detroit trutrac. Didn't break a sweat taking 600hp. Now it's backing an 800hp Foxwell 532" motor, a modified TKO600 and RAM 10.5" dual disc clutch. I'll report back if anything breaks :lol:

Re: rear axle advice
 

My 468 dyno'd at 600hp and I'm hitting it with a 250 shot. My 12 bolt rear end is completely stock except for a mini-spool in an open diff. Not sure what the truck weighs but its an all stock 68 short bed step side. 3.73 and 28" slicks.
I just tore the rear end apart to re-gear and all looks good. I did however weld the tubes to the center section and added 3" studs. I'm kinda scared of the mini-spool/cross shaft breaking but it looked great. Hopefully it stays together until I can get a full spool and upgraded axles.

Re: rear axle advice
 

I run a truck 12bolt @ 3:73, stock width, welded by someone before me. Its had Moser and Strange axles, and survives ok under my fairly heavy truck on steel wheels w/ 325/50/15 MT's. I make a bit less power than some folks, only around 460 + a shot 75-175.

Re: rear axle advice
 

I did much the same, though I narrowed mine 7" total (3.5" per side), and also installed studs in the housing for the carrier bearing caps.

http://i6.photobucket.com/albums/y20...0/P1230100.jpg
http://i6.photobucket.com/albums/y20...0/P1230322.jpg
http://i6.photobucket.com/albums/y20...0/P1240605.jpg

Re: rear axle advice
 

^nice trailing arms. Home made or purchased?

Re: rear axle advice
 

Thanks. I made them.

Re: rear axle advice
 

Thanks for all the info. I originally planned on 4.11's but it seems like a few of you run 3.73's. With the amount of freeway driving in Phoenix I might give the 3.73's a try.. One other question is about how much to shorten the axle for larger tires. I haven't given tire size much thought other than running drag radials. Those of you with shortened axles what size tire do you run and how many inches did you have to cut off?

Re: rear axle advice
 

You'll need to know what wheel offset/backspacing you want to run. I took a bunch of measurements, then drew it all up in CAD before cutting anything. I ended up shortening the axle 7" total, widened the tubs 5-3/4", moved the front of the wheel opening forward 2", and formed 1/2" roundstock to the shape of the new wheel opening and then cut/rolled/welded the lip to around it to gain another 1" per side. I have two sets of wheels. Both are 15x12" with a 33x16-15 tire. One set has 3.5" of backspace, the other has 4.5". Both fit well.

This photo is old, but shows the bed in place. The truck sits lower now.

http://i6.photobucket.com/albums/y20...0/P1250810.jpg

Re: rear axle advice
 

I killed a clutch type posi at the track with only 10psi on a 5.3. They just can't take the torque of a turbo. Switched to a Detroit locker, and even though it certainly changed the streetability of the combo, so far no more issues at the track.

Since I'm being contrary, I don't like drag radials either. Brutal on parts with no sidewall flex and inconsistent unless the track is well prepped. I love a slick for drag racing!

Re: rear axle advice
 

100% agreed.