I have a 70 Chevelle that makes about 1200 rwhp and weighs about 3400. I had concerns about breaking the 12 bolt so I want to build a 9". I have narrowed a few rears before but this is my first complete build. I already have a 4WD housing and replaced the tubes with 1/4" wall DOM tubing and plan to brace the back of the housing. Should I tig weld all of it together or mig it? Before I weld the tubes and brace should I prewarp it before I weld?

Center section, I would like to use an aluminum case but will they hold up to the power and weight I have? Also noticed there are quite a few out there, Strange, Yukon, and Moser to name a few, any of them better than others??

Axles, 35 spline sufficient?

Any help is greatly appreciated.

 

I usually do the MIG weld deal.
I tack weld all the components.
Skipping around also helps cut heat build up.
I install the ends, making sure the fixture bar slides freely thru the dummy brgs, as I weld them on. You may check for warp, by looking at the ends vs the ends of the tubes.
Warp? Get it straight, then proceed w/ the ends.
I also buff the back sides of the stud holes w/ a ziz wheel. This allows the studs to pull up tite against the flange.
I also chamfer the outer ends of the holes, to allow the sealer to form an "o'ring" around the studs. I do this to the inside of carrier holes, too.
I find that grinder dust, etc, is captured in the rolled inner lip of the hsg. That HAS to be cleaned, B4 assy.
I use the lube resistant sealer, and no gasket.
I also add a "V" notch where the hsg meets the tubes. This gives more weld area, to retain the tubes in the hsg.
My latest hsg uses the Grizzly nodular carrier and their version of a Det locker.
As for the alum center. Some folks say that you can experience shorter r & p life, vs a cast iron piece, due to more deflection. No personal experience here.

 

Thanks for the reply Chuck. Do you offset your axle tubes forward so that once your complete welding they will draw back? Also, I was thinking about welding the housing ends on very last to make sure everything else was perfect.

 

No offset. I have a fixture that fits both the tube end, and the brg flanges. I start out strait...

 

Makes sense, thanks Chuck!

 

U R most welcome!

 

Ok, next question. I purchased 3.25" OD DOM tubing for the axle tubes. The original axle tubes were pressed in like an inch. How far should I press the new ones in?

 

If you have long enough tubes...you can't go wrong with bringing them in 6"-8" or so. Fab a pair of 1/16" or 1/8" thick rectangle plates the size of the inside of the housing in that area with a 3 1/4" hole in the center...slide the plate over the tube a 1/4" & weld it all up. Leave the lower corners of the plates open if you have tapered axle bearings that require oiling. Likewise if using the vent in the axle tube, leave the top corners open. I typically just nip all of the corners off & just weld a 2"-3" stitch on the 4 sides...no need to weld solid & less time to get fitment. This method will strengthen the housing as well as the tube mounting. Lorne

 

Thanks Lorne, I like that idea. I have been looking to see if I can find some pictures of that type of brace but no luck yet.