Im looking for the years C3s that used a 4 speed driveshaft with a 1330 u joint on each end. Im doing a big block swap and have spicer 1310x1330 conversion u joints on each end. Trying to do a search for specs isnt a possiblity, I've tried
thanks
scott

 

My e79 4sp
used them
https://www.rockauto.com/en/moreinfo.php?pk=4937352&cc=1041118&jsn=4

https://www.corvetteforum.com/forums/c3-tech-performance/4467025-u-joint-driveshaft-retainer-torque-verification.html

 

I have run down that rabbit hole recently myself. From what I have learned (and am not saying it’s gospel by any stretch), while the rears were built with 1310s and 1330s, there never was a 1330 front joint. You can buy a 1350 Front/1330 Rear but you may run into some tunnel interference. I am currently in the process of having Denny’s Driveshafts build me a shaft with a Mark Williams detachable 1350 on the front with a 1330 rear. I know the 1350 is overkill but I don’t want to put a 1310 in and no one makes a 1330. I have spoken directly with Mark Williams as well as Sonnax and they both say there just isn’t any market for them to invest in making the 1330. I’m not worried if I get a little rub as doing a little ‘glass surgery is not a big deal.

 

Kevin

I went down that rabbit hole lately as well.
I tackled it from the viewpoint of how much TQ could the Spicers handle, and how much stress does the engine put on them (with the trans)
The conclusion I came up with was the 1310 front U Joint is acceptable in most all normal applications

C3s Application Data:
1310 end of trans
1310 or 1330 front of diff
1350 half shafts

Spicer Data:

They don't break at the yield point, they just permanently bend and do not rebound. They will only handle so much of that abuse.

Torque Applied to trans U Joint (per Spicer)



The numbers say that neither a 1330 or a 1350 gains you very much on a driveshaft. With a stickshift.

Now if you have an automatic, and a high stall torque converter that stalls near the peak TQ of the engine, you probably know a lot about breaking stock driveline parts!. LOL

I wonder what AJRotham is running in his 496 auto monster?

I am actually "cutting it pretty close" with a 2.87 1st gear in my 550 TQ LS6 with a 1310 in the front.
I'll have to keep an eye on it I guess.
But that is the std size output yoke on the 600 lb rated TKX 5spd.
.

 

We ran a TKO500 with 1310 slip yoke from good ole Keisler. It leaked oil out the plug because they didn't seal them but it didn't matter anyway because the 2nd or 3rd pass at the track and it twisted. We went with custom driveshaft, a 1350 MW slip yoke and 1350 billet pinion yoke. Victory made the slip yokes but Mark Williams also made some for Tom a few months before he passed away. I know because Tom had me proof them. They were good but I like the Victory yokes better.

By 75 with only 2 350's offered they used 1330 yokes. If you go 1350 you have to glass a small area on the passenger side of the tunnel and once under the carpet you won't know.

 

2013- 75 vette, 450 at the wheels, 4-5k RPM launch, dead hook. 1/2 shaft & flimsy half shaft loop became instant junk.

 

Leigh,

I appreciate the input. I’ve studied the Spicer data and am familiar with the respective torque capabilities of the joint size but at the end of the day, the Dyno said I have an engine with a torque curve that provides 500 lb-ft from about 2800 through 4500 rpm. At peak horsepower (505 @ 5600 rpm), it is kicking out 440 lb-ft so I’ve decided to put the 1310s on the shelf. Gary’s pictures reinforce that decision.

I have a QuickTime bell housing to ensure I keep all 10 toes intact and I’ll have a 1350 MW yoke to ensure my right elbow continues to function normally!

 

I am running 1350’s on both ends on my 69. No interference at all in my stock tunnel. I have a Richmond 5 speed. The problem comes when a transmission longer than a Muncie ( like a TKO) is used which pushes the yoke back into the skinnier part of the tunnel. Below is a link to the transmission yoke I am using. Really nice and plenty of room under there with it.

https://www.moserengineering.com/ty7...50-series.item

 

 

that 'll do. Looking for a 71+ driveshaft eventually, cool

 

Duh! I thought my car had a 1310 front yoke.
I just went and measured it and my 72 BB driveshaft is 1330 at both ends.
So I am going to have to re-think this whole TKO "1310" yoke thing!
I was planning on ordering the trans today. Maybe not. I should figure out the driveshaft thing first.

Now Gary's half shaft pics bring up what I believe is the weakest link in the C3 IRS, the half shaft 1350s, even the spicers.

I made this before:

Now this brought up two points:

1. My 550 TQ BBC will put 2750 lbs to each half shaft, and that is more than the 1350 will take often. They are only rated at 2260. So I am 22% over. That's definately not good.
2. That much TQ will cause the 2.5" dia half shafts to twist 62% more than a SB. That's not good either.

Even an L88 with 456 gears would not strain the IRS this much (With a rock crusher). It's the deep 1st gear in the TKO trans that does it.

So to fix problem #2 I am using 3" GM halfshafts
Problem #1 is tough. So the Spicers are the "weakest link" Sort of like a fuse.
Gary thinks the outer axles are just as weak as the spicers, or at least similar, so another "fuse"

So my solution is to keep street tires on it, and let them be the weakest link, and never use slicks, and hopefully that will be enough.
So if anything "goes" on mine, it should be "around" the trailing arm area. Keep your fingers crossed for me!

(I also did not deduct 15-20% for driveline friction loses. That should give me a little more breathing room as well.)

 

Kevin;
If you are going to go to the strip, and do some hard launches, that is probably a smart decision.

I am going to stay away from that, especially the slicks.

Oh I just noticed you plan on a TKO and 373s so yes, strength becomes a problem.

 

So I just did some research and it looks like Denny's driveshaft offers a 1330 TKO yoke.
My muncie yoke and the TKO have a different spline count: 32 and 31 spline output shafts, so that yoke is out.
The 1330 u-joints should be a 15% stronger than the 1310.
I'll be loading it with 1500 TQ and the 1330 Spicer should be good to 1850.
So I should be OK there, "under my elbow"
The 1350 is worth another 20% but I will pass because of the tunnel mods and I do not think I'll need it.
So I will keep my 1330/1330 driveshaft setup, and either modify it or buy another for the TKX.

On the half-shaft mounted 1350s, they are rated at 2260. My BBC with a 3.23 rear and 2.87 TKX should put 2750 TQ to the ujoints. I forgot to take a 20% deduction for driveline loss, so that would be 2200 at the 1350s.
It is awfully close to what the 1350s are rated at.

I'll just stay away from the hard launches and keep an eye on them.

At least this conversation gives me some confidence that I can drive it without breaking it. (Some of the time anyway).

 

I think the 31 and 32 Chevy yokes are the same, as the yoke I am using was a 32 spline but fit my 31 spline Richmond. Ford has a 31 spline that is different. Could be wrong but seems like this was the case.

 

Leigh, no plans for racing at all. Just trying to find a balance between:

A. Throwing money away on stuff that doesn’t add value
B. Not spending money on something I should have
C. Getting wrapped around the axle (no pun intended) trying to determine the weak link in the drivetrain
D. Dealing with my OCD on making everything perfect
E. Recognizing that the true goal of ownership is enjoying the car

When I find the answer, I will let you know!

 

Leigh that 20% driveline loss isnt correct, the driveline is a set loss. So if you have an old dyno pull or can find someones dyno results for the same driveline (transmission, differential ratio) that loss would be the same. What Im trying to impart is that if you lost "x" number of horse/torque with a 300hp motor with your driveline, you would loose that same number, not the same percentage. So in your case your 20% number would be high giving you more torque than you think. Im in your boat with worrying about torque vs running gear. My 327 ate up 2 different rearends, one a 3.70s spider gears, and a 3.55 of undetermined damage. I was building a 427 trying to stay under 500 ft/lbs just to keep the transmission alive. I have a 396 that will be in the lower 400 ft/lbs so Im safe for now, but when that 427 finally gets built I have to upgrade the tranny.

 

Interesting subject, and applicable to my intended build on my 69. I have been talking to Mark at Vortecpro about building a big block for the car, and torque is the primary build focus, but we seem to have this problem with stock driveline / transmission. Now, part of this may be that we could "self regulate" how we drive the car, i.e. no hard launches, ......but then what is the point of spending money on big torque if you can't use it. I think that is what Leigh and others are concerned about, rightfully so, as its a realistic and valid issue. For me, it makes my decisions easier to have VortecPro build me a LS5 454 (increased to 468), with the same theme that Mark built the 427 he recently documented in this forum. I like Marks thinking. Build a big block, with factory GM used components, and build the motor with all his "tricks", producing way better power than stock. It comes in at way less money than using aftermarket components, AND we don't end up with excessive torque / HP that is basically unusable with the C3 Corvette driveline / transmission. I really want to stick with my Muncie 4-speed, I can use whatever shafts / u-joints that are best, and will have a Gary Ramadei differential......so, this sounds like a plan. I hope this thread generates some data on the best choices for driveshafts, half shafts, etc,.......and IF there is a better transmission, what it is. As much as I would prefer staying with my original Muncie 4 speed, I could be swayed into a different transmission....so interested in how this thread progresses.

 

So the last couple days I did a lot of research into driveline strength, ujoints and shafts.
It is so easy to build HP and TQ in this day and age.
And this 50 year old design will only take so much.

Silversport, Ft Wayne, Denny's, internet. All basically came to the same conclusion.
A 1310 ujoint should be able to handle 500 HP OK, maybe even 550 OK..
Like on the driveshaft. (Many Camaros run them.) Depending on how much you drag race it.
That's about it.
Guys have drag raced 1310 d/s for years and run 12s, 11s or even 10.9s
One guy using 1310 even had his heavy 625HP Chevelle going 10.3s and they were fine.
These guys run slicks and hard launches. I won't be doing either one of those, or at least not very often. so I think I will be OK on the 1310 driveshaft front ujoint.

My math calculations say the half shaft 1350s are much more "at-risk" anyway (vs the drive shaft) because the power gets multiplied by the diff gears. I am moving up to the 3 inch GM half shafts. So that leaves the stock 1350 ujoints. Those and the rear axle stubs seem to be the two hard parts most likely to break. And at somewhere around this HP level. It is all depending on the frequency and violence of the abuse, and the traction levels. (Gary)

Silversports TKO std is the 1310 trans yoke and they have never had an issue there with over 300+ customers. Problem #1 is no one makes a bolt on 1330 yoke for a 32 spline TKO. Problem #2 is the 1350 yoke is available but is so big it requires fiberglass mods to the tunnel. But it is do-able. Those ujoints would be a good 30-40% stronger if someone is interested, or has more power than me. I know some of you do..

Gene (there) has a 485 RWHP LS / 70 C3 with TKO and a 1310 yoke.
The driveshaft is not a problem and he drives it hard. His comments were enlightening.
He has way more "issues" with traction. Ralleye wheels and BFGs and he has completely "lost it" on full throttle in a curve in 1st, 2nd and even 3rd.
They just do not have enough traction. LOL
Going sideways or backwards in fiberglass is just not cool and destroys your Fonzi image!

It's nice to have that kind of power, but I forsee another prudent upgrade in the future so I can "use it"
18s and some wide HP street tires.

"While I was at it" strikes again!

 

Flyboy58, I bought my 69 2 weeks after returning from Vietnam in 1972. It was built with a 350/350 and M20. Over the years, when people found out I owned a Corvette their first question was what year is it and when I answered that, they asked if I had the big block. After hanging my head, I had to mutter “no”. So, about 20 years ago, I started searching for all the parts to build a period correct 2nd design L88 with all appropriate date codes. I wanted to build a driveable car that looked and sounded like an L88 but without any intentions of running it hard. However, after a lot of reading and research, I became aware of the C3 driveline limitations that have been extensively addressed elsewhere in this forum so knew from early on I needed to be respectful of the fact that I now have 500 lb-ft of torque vs the 380.

I bought a TKO600 new many years ago as it solves 2 basic problems - first, it will handle 600 lb-ft so is more than capable of dealing with my engine, second, the overdrive takes care of excessive rpms at 70 mph. It has slightly lower 1st gear ratio over the 2.52 muncie’s. I am currently evaluating getting a TKX as I have never installed the TKO and I have read about hard shifting on the TKO but that is another story.

Through this forum I “met” Gary Ramadei and he was instrumental in my learning how to properly build and tune my differential. I won’t go into all the details in this post (it would be extensive) but the major changes I made to my 69 unit were a third design posi with 17 tooth spiders (from Tom’s), US Gear 3.73s, Muskegon Brake rear cover and a pristine set of HD axles. If money were no object, I may have gone “all-in” and built the differential with the flanged axles and 30 spline spiders and put in Tom’s Kick-*** outer axles coupled with the 3.5” halfshafts. However, due to the fact that Tom Watt passed a few years ago, some of these components are no longer available and I honestly found it hard to justify the expense if they were.

I am very confident that how I built my differential will serve me well. The issue I still have (as does Leigh1322) is how best to address the driveshaft/halfshaft/u-joints. Specifically, where to spend money that makes sense and where not to.

With all due respect to Leigh1322, as he has made a lot of excellent contributions to this forum, I would not place a lot of credence in the claim “they’ve never had an issue with over 300+ customers”. While that may be true with them, there have been a lot more than 300 people who have put a TKO into a C3. American Powertrain (where I got mine from) supplied a 1310/1310 driveshaft but also offers a 1350/1330. There is a reason GM put a 1330 pinion yoke on later differentials - the ability to handle increased torque. The problem today is that you can’t buy a 1330/1330 driveshaft because no one makes a 1330 output yoke for the TKO, hence the need for the 1350 and the tunnel mod ( which is a relatively small job).

As I see it, assuming (I hate that word but will use it anyway here) your differential is not going to break first, the question is then what will - the 1310 transmission yoke, 1310 u-joint, the driveshaft, the 1330 pinion yoke, the 1330 u-joint, the the 1350 joints in the halfshaft, the halfshaft or the outer axle?

The transmission yoke I got from American Powertrain doesn’t give me any confidence so I am looking at a Mark William detachable yoke so I am not going to worry about that for $350. I have not heard (doesn’t mean it has never happened) of a 1330 pinion yoke failure so let’s cross that off the list. Next, same for the driveshaft - doesn’t appear to be a prime concern (but for about $400, Denny’s will build you one you don’t need to worry about).

So now it come down to a race ( no pun intended) between the 1310 transmission u-joint, the halfshafts, the 1350 halfshafts and the outer axles. Leigh mentions above that he (Gary) thinks the 1350 halfshaft u-joints are as weak as the outer axles but in the pics Gary posted of the busted halfshafts, there is no mention of what outer axles were in the car. Assuming they were stock, I would concur with that assessment.

At this point, you can make a cost/risk mitigation assessment. You can spend around $700 to put a Mark Williams detachable 1350 transmission yoke onto a Denny’s driveshaft and completely eliminate all concerns over a “upstream” (of the differential) failure. You can spend $600 for a pair of Denny’s Nitrous Ready halfshafts but you will get the same 1350 greaseless Spicer u-joints. I don’t know the relative strength differences between the stock halfshaft and his but fresh metal is generally better than tired metal.

You could spend $1000 and put in the Kick-*** outer axles or you could up the ante and spend $3000 for a set of Tom’s 1480 u-joint halfshafts and axles but that will require battery box alterations and a differential disassembly). Clearly, that would take the “downstream” concerns out of the equation but now you will have to factor the differential (the posi unit) back into the equation (assuming you’ve gone all-in and addressed the “upstream” issues).

And, finally, you could go full monte and buy the Mark Williams posi, inner axles, halfshafts and outer axles and drop $8500 which would likely cause you to think about converting to a 12 bolt posi because the 10 bolt gears may ultimately become the limiting factor then. At this point, the equation Velocity is directly proportional to Dollars Cubed comes into play.

A lot to consider. Everyone’s situation is different and everyone will have their own view of what “feels” right for them. The important thing to always consider more are facts as opposed to opinions. Continue to read up and be as fully informed as possible.

 

Yeah Kevin and Flyboy we are all in the same boat. Trying to add some more HP without breaking a lot of parts. And trying to spend the money where it is needed the most.

The clincher for me on the driveshaft was the guy running 10.3s in a 625 HP Chevelle for several years. That must be a wheelstander to do those times. I can only imagine how short the 60 ft times are.
I will never put that kind of strain on my Vette. If I were to drag it regularly, or autocross a lot, I would make a different decision. On a lot of driveline parts.

So I'll stay with the 1310 at the trans and spend my money elsewhere. I might not get OEM 50k mile reliability out of them, so I'll just inspect them closely every year or two. I'll probably have to put my solid rollers on a similar close inspection schedule anyway.

I am not trying to convince you out of doing what you are comfortable with. This is what I have become comfortable with. And I appreciate the discussion, it really helped.

It's looking more & more like I'll need to save some money for tires and wheels anyway!

Oh and Kevin, I almost pulled the trigger on the older TKO last year. There are some shifter mods, brass tipped forks, synchros, etc that change the shifting pretty drastically and give it 7000 rpm capability. It was only $500 in mods. Something you may want to check out since you already have the trans.

Tremec also recently told me that the TKX synchros are completely redesigned with that specifically in mind, use carbon fiber and double syncros are now std, and shift smooth as butter and to 7000 with no mods. That and the trans has a new better midplate making it stronger.