c3 half shafts
Tech Contributor
Joined: Jun 2004
Posts: 20,864
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Man, I can't believe I can't find an old post of mine anywhere where I mentioned the weight of my halfshafts. I finally just had to blow the dust off one of the spare C4 halfshafts laying on the shelf and weigh it for some kind of a baseline. With both u-joints still installed, the halfshaft was 7.1#. I don't have any spare C3 shafts laying around to weigh (the original '69 shafts are still bolted to the original suspension), and I did a search in the C3 Tech section but struck out finding any weight info regarding C3 halfshafts. It would be handy if someone here was able to get an accurate weight of a C3 halfshaft. When comparing the shaft weights, we have to remember that stock C4 shafts are over 4" longer than C3 parts (which is convenient for anyone wishing to change to aluminum shafts economically).
Edit: Just made a quick calculation of the weight of the extra tubing length (compared to the C3 halfshaft length) in a C4 halfshaft. It comes out to pretty much .4#, which would yield a C3 length replacement weight of 6.7#.
Edit: Just made a quick calculation of the weight of the extra tubing length (compared to the C3 halfshaft length) in a C4 halfshaft. It comes out to pretty much .4#, which would yield a C3 length replacement weight of 6.7#.
Last edited by 69427; Jan 15, 2019 at 07:59 PM. Reason: Added content.
Thread Starter
Cruising
Joined: Jun 2012
Posts: 10
Likes: 0
From: Archbold, Ohio
c3 half shafts
Wow, thank you for all the responses so far. I know a lot more than I did, but I still am not sure which way to go. I am not worrying about the weight difference, more about the strength. I won't be doing any drag racing, but with the power that my engine has it's sure fun to do some pretty aggressive driving. I would be interested in hearing any recommendations either way.Just to be clear, all 1969 corvette half shafts use a spicer 1350 U joint? Thanks again for all your responses, I will be waiting for more,.bvette 1000
Tech Contributor
Joined: Jun 2004
Posts: 20,864
Likes: 960
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Wow, thank you for all the responses so far. I know a lot more than I did, but I still am not sure which way to go. I am not worrying about the weight difference, more about the strength. I won't be doing any drag racing, but with the power that my engine has it's sure fun to do some pretty aggressive driving. I would be interested in hearing any recommendations either way.Just to be clear, all 1969 corvette half shafts use a spicer 1350 U joint? Thanks again for all your responses, I will be waiting for more,.bvette 1000
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
Are you sure? Unless you know the actual wall thicknesses, and do the math, you're just guessing.
IIRC there was a similar thread a couple years back. With the (rumored) wall thicknesses of the 2.5 and 3.0 inch halfshafts, the 3" parts calculated out to be both lighter and stronger.
If you know the true, actual wall thickness of these halfshafts, post'em up. The math is pretty simple after that.
IIRC there was a similar thread a couple years back. With the (rumored) wall thicknesses of the 2.5 and 3.0 inch halfshafts, the 3" parts calculated out to be both lighter and stronger.
If you know the true, actual wall thickness of these halfshafts, post'em up. The math is pretty simple after that.
Thread Starter
Cruising
Joined: Jun 2012
Posts: 10
Likes: 0
From: Archbold, Ohio
c3 half shafts
OK. All the info that all of you provided for me helped me make a decision .I m going to use my original half shafts and spicer 1350 ujoints. I have a chance to put a set of street slicks on, but everything I have read say this would be a big mistake. I am very interested in reading any thoughts on this subject. Thanks a lot everybody for all you help. bvette1000
i
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Burning Brakes
Joined: Jan 2012
Posts: 943
Likes: 73
If you keep the same half-shafts, my recommendation would be to remove them and take them to a good driveshaft shop to have the U-joints replaced PROPERLY. Simple and inexpensive job, and it will eliminate any possible [unintentional] damage done by you. For strength, install U-joints without lube capability (no cross-drilled passages nor Zerk fittings).
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
OK. All the info that all of you provided for me helped me make a decision .I m going to use my original half shafts and spicer 1350 ujoints. I have a chance to put a set of street slicks on, but everything I have read say this would be a big mistake. I am very interested in reading any thoughts on this subject. Thanks a lot everybody for all you help. bvette1000
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i
FWIW, FT Wayne Clutch and Drivetrain sell a nice set of 3" x .095" wall half shafts with solid 1350 spicers for about $270 shipped. They are usually on the shelf and ready to go, you'll just need to press the outer flanges on them, or buy a set of flanges from them and have them installed. I've ran these same half shafts for 9 years and about 100 passes at the track in the 10s.... They are cheap and they hold up.
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Le Mans Master
Joined: Oct 2004
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From: Orlando Florida
St. Jude Donor '05
long time no talk man... hope you're all right during this Virus.... 2020 sux so far... well, on the shafts it will take some torsional calcs to figure out which is stronger, GM is cheap but not stupid so looking at the cost increase to change design, supplier specs etc I doubt the 3" shafts were just a brain fart... why they decreased the wall thickness no clue... especially while HP and torque decreased over those years...
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they decreased the wall thickness while increasing the diameter saves weight and improves or retains the strength. I looked at getting the 3" and there are a lot of old threads on this.