I am looking for some advice as to where to buy a good set of axles. I am rebuilding an iron differential to put in my 80 Corvette to replace the aluminum one. I am looking to buy new not rebuilt. I keep hearing how people are getting axles that are to soft and wear out prematurely. I have also heard the snap ring groove is not deep enough or wide enough. My current engine puts out less than 450 HP. I am also running a TH350 but considering a 4 speed. The rear gears I have are 3.36. I was planning on putting a 421 SBC that makes around 550 HP but I don't know how long the rear diff would last. I assume most venders buy their axles from the same supplier. I would appreciate any recommendations. Thank you.

 

Iron Will, here are my (probably unpopular) thoughts. I too have a aluminum diff in my 82. Knowing that the rear ain't the strongest (the iron diff isn't exactly the Holy Grail of diff's either) I limited my horsepower and aggressive axle ratio selection to a more conservative combination. If I was building a 550 horsepower 1980 Chevy, I would build a 1980 Z28 and install a Strange engineering 12 bolt and forgot about that IRS nonsense. Z28's handle fantastically and great looking too.

 

I should have mentioned i an sticking with the 350 SBC that makes less than 450 HP. I am converting to the iron differential for the extra strength. My main concern is find a decent set of stub axles.

 

I've asked this question in the past.
Other's have asked this question in the past.
We keep getting told how bad the quality is with replacement side yokes.
How 50 percent of them are junk, etc. etc.
But still waiting to actually hear where we can get a decent yoke!

 

Doc,
I have had the 50% rejection on certain axles. The 50% that passed my inspection were good, never had an issue with them. The 50% that failed my inspection were never installed in a diff and returned. Simple as that.

I have seen other rebuilt axles that I would never use under any instance.

I have seen new axles that are case hardened which original C3 axles were, so that give them a lifespan of about 50k miles.

I have taken apart original 63-67 diff's with over 100k miles and the axles had less than 005" wear.

A couple of years ago my buddy was building a 63 SWC for his wife. He bought new axles since the car had a 69 diff in it. I checked them and they were not impressive, 045" endplay in a common spring loaded posi. I tuned the posi and they were still in the 020- 025 range. That is not good for a rebuilt differential.

I use good used GM axles that I have had hardened and tempered, then cryo treated.
I use those 50% of good rebuilt axles.
I even stock some new case-hardened axles for those who need an axle to keep going and cost less.
I use 30 spline axles, Tom's to be specific, not the knockoff's. I have them also hardened and cryo treated. They work for various applications.

I have my built iron diffs in cars up to 900hp. They are not stock, nothing close to stock, they are also not bulletproof as anything can be broken.

I do not stock any 80-82 diff's or parts, nor will I ever use them again. This is not said to create a debate, I just won't use or take them in.

So, to answer this question in a reasonable manner, anyone buying an axle today should know what to look for, ask questions, and inspect it when it arrives. Blindly buying an axle may or may not work well or for long. I would buy from a supplier that will not hassle you if you want to return it. Some will, some won't.

Good luck.