1974 L-82 4 speed. Putting in new u joints since I have the diff dropped right now. I have the "heavy duty" differential, I know this because it uses caps instead of u bolts on the yokes. Not sure which u joints to buy. What is the difference between HD and regular U joints? Are they different sizes, different specs, and what came on the the car from the factory? Thanks for the help.

 

Assume you are primarily referring to halfshaft U-joints. No difference with regard to a “HD” (or not) differential.

If you want the strongest joints, get the Spicer greaseless.

Have you checked how much end play you have in the stubshafts?

 

The solid ones are stronger.

 

Myth about a HD diff

 

Alright so the spicer non-greasable 1330 and 1350 are the best? The is a bone-stock 74 L-82 (other than headers) which they say has 250 hp... so not worried about snapping a u joint. I found these on amazon for the best price... thanks for the recommendation!

 

My 77 4 speed L82 was rated at 210HP. Man I've blown that many half shaft U joints. Get the good ones!

 

Ok, it seems you're looking to use lowest price items RATHER than best made product.
You can't have both. You now have all the information to make your decision. So just pick what you can afford.

 

IF you don't need to use the stronger solid U-joints, I personally would use the grease-able U-joints. My BB C3 Needs the strongest U-joints as they can and have blown apart on this engine. My C4 does can use the grease-able u-joints because it makes a paltry 255 hp and doesn't stress anything.

I have the set of half shafts on the car and a spare set at home with new solid u-joints.

The most important thing to check it to be absolutely sure that your shafts are as flat as they can be. Any angle on the shafts and they will start to wear the u-joints right away. Be sure to use the right length bolts on the ends of the rear spring as this can affect the angle of the half-shafts as well as ride height in the rear. With Shorter bolts my rear end looked like it was "Jacked Up" and my u-joints were howling while driving. The longer bolts allowed me to put the rear where it belonged and I no longer saw the rear in my mirror.

 

Look at the torque rating of the engines and you can see why the u joints can fail. They are rated on torque not HP.

A friend had a Firebird 455HO Trans An 500'/# of torque, rear tires and u joints were an issue..
.

 

Unless you plan to drive a 50 year old car as a daily driver, piling on 10s of thousands of miles annually, you don’t need to worry about the non-greasables.

 

You may want to look at Rock Auto for price and selection.

 

👍 Just FYI, Rock lists the Spicers under the Dana parent company name.

 

FYI, buy from a place that will help you if you have any issues with the parts. I just bought 8 -1350's and they all had the wrong clips in them. Bought 4- 1310's and one was a zerk joint. The Spicer crosses are larger and will require fitting to get them installed. Any variation in the flange- slight bending, you will not get the clips installed and without the correct clips in the first place unless you have a surface grinder or clip stock, good luck.

 

been couple years but rockauto less than 120 for all 6

 

I’ve always been happy with Denny’s Driveshaft.

 

I agree with the 5-1350-X being the half-shaft u-joint to use and with GTR1999 about fitting them.

I just returned from PRI where I spoke to a Spicer rep who does failure analysis on returned, failed joints. I picked up two interesting tips:

1. There is now a 5-1350-XP out. There is no difference in strength, but the XP has higher-temperature grease and seals to match that temperature rating. They get positive feedback from the field when used in harsh conditions, such as offshore marine racing.

2. Between the end of the trunion and the cap on the 1350-X there is a plastic material thrust washer. Be careful when disassembling the joint for installation that the joint goes back together with one thrust washer per cap. The washer may stick to the trunion or may remain in the cap when disassembled. Failures and/or vibrations have happened when the thrust washers were not equally distributed.

 

This isn't a job you'll have to do every year. It could easily be a job done once in 10 years. I see absolutely no argument to be made for attempting to save a couple of bucks on anything less than the strongest and most durable u joints you can get out of the standard offerings out there. My reasoning is simple. A drive shaft failure is not likely to ever be a big deal problem in a C2 or C3 corvette. Very short length and unlikely to fall to the street if it ever does fail catastrophically damage and danger isn't of too much concern. The same, how-ever, CANNOT be said of the half shafts. Catastrophic failure here can do a lot of very expensive damage. Enough to warrant at least a yearly peak and check of things. Any hint of a problem or even if I'm looking at them and it's been long enough that I just suspect the grease inside may be starting to dry out and I'm pulling them out and replacing all 4. KNOCK ON WOOD......I've owned my C3 for more than 40 years and I've never experienced a half shaft failure. These days the car is powered by a Blueprint engines 400In engine making big torque and 500+ hp. The 2,400RPM stall converter "HITS" hard on standing WOT take off......so I do think about this more than I used to when the car was new. Regardless of power levels though even stock "smog level power" will easily break a dried out joint that heats up enough while running. Sometimes you hear the "Clunk" and obvious noises that alert you to swap out old for new but you're already living dangerously by the time you hear the problem. EVERY OWNER should be checking this part of their car on regular basis. Every oil change certainly seems like a good time to do it. The car is already in the air and it only takes a couple of extra minutes.

 

I literally selected the parts that were recommended to me as the best, what more do you want from me... maybe next time I'll search for the most expensive offering of the same part

 

Thanks for all the info everybody! The parts came in quickly and correctly... 2x 1330s and 4x 1350s spicers, all non-greasable, and each one came with three sets of snap rings. I also have all new hardware coming in from Zip. Now on to cleaning and painting these shafts...