[craigs69]

Adam, I would not run a conversion U-joint and I would recommend Spicer non-greasables. They were highly recommended to me by Precision Gear years ago when I was mud dragging. I ran Spicer U-joints launching a 4800 lb 4x4 Chevy truck off the trans brake at 5500 rpm in 2 feet of mud with 38" tall irrigation tires and never had a u-joint failure. I would change them each season and they always showed signs of deformation on the needle bearing surface, but no failures in 7 years of racing. Needless to say, I'm running them in my Pontiac. Denny's uses Spicer u-joints in all of their heavy duty driveshafts.

[AdamIsAdam]

Originally Posted by craigs69

Adam, I would not run a conversion U-joint and I would recommend Spicer non-greasables.

So what do I do? Get the new driveshaft made with 1310 end?

I'm learning, but having trouble with terminology. I'll ask some basics. Correct/interject as needed:

1) I understand 1310, 1330, 1350 is just a size difference.
2) What diff yoke do I have? It's a stock BOP 8.2 What size and name is that? Is it Saginaw 1310?
3) I cannot find a 1350 yoke for an 8.2. Does anyone make one?
4) What tranny yoke is in my Muncie? (which is an M20 case built with M21 gear ratios)
5) I've read that non-greaseable u-joints are stronger. (No hole drilled, makes sense to me.)
6) I've been told conversion u-joints are not a permanent solution but don't understand why (and can't find any without grease fitting holes drilled)

Assuming I cannot upgrade my diff yoke, which is probably ok for my application, what is the best solution? 3" steel Strange driveshaft but have it made with 1310 end so I can run a solid 1310/1310 u-join? One manufacturer suggested using 3.5" aluminum shaft since it will provide more flex than steel, thus absorbing some of the torque on launch.

I want to do this right. What's right?!

[AG]

A 1330 joint has a 1.062" diameter, 1350 is 1.188" and a 3R is 1.125". I know they sell a 1330 to 3R conversion joint, but not sure if a 1350 to 3R is made. If you build a driveshaft, use the biggest rear u-joint made. You might be stuck with a 1330 to 3R. If you are going to hammer on the car, just get a rear you can get a 1350 u-joint such as a 8.5" or 12-bolt.

[AdamIsAdam]

Thanks, but that doesn't really answer any of my questions. I'm not changing my rear.

[AG]

Have a 3" driveshaft made using a trans input with a 1350 u-joint and use a 1330 rear weld in yoke and a 1330 to 3R conversion joint. Your stock rear is 3R.

[AdamIsAdam]

So I'd need a new tranny yoke I guess, right?

[AG]

If you get a 1350 u-joint for the input yoke you will need a new yoke. You can use your existing trans input yoke and use all stock size 3R joints on both ends, unless a weld-in 3R yoke isn't made for the rear of the driveshaft.

[RocktimusPryme]

Originally Posted by AdamIsAdam

Thanks, but that doesn't really answer any of my questions. I'm not changing my rear.

I assume the A body is in the same situation my F body was. Only I do plan on changing my rear end down the line. But in the here and now it was the same.

He put a nice slip yoke on mine for the th400 and connected that to the driveshaft with a 1350. So if you want to use a larger Ujoint at the front, yes you would need a new yoke.

At the back I also asked about a conversion joint, he basically said it didnt matter. That the weak point was the weak point. In this case the 3R to the BOP rear end pinion. So really even the 1350 up front doesnt really matter, because the weak point is there anyway. BUT in my case when I upgrade the rear (provided its to a unit that wants a shorter shaft) I can then use a 1350 pinion, upgrade the shaft to a 1350 joint and then I would have the larger joints all the way across.

Maybe its better to have a break point in the rear than the front? In that case yeah the 1350 at the front might be a good idea even if you cant put one in the back. IDK. Seems like it would be better if it failed farther away from the driver.

He did also suggest joints that dont require greasing as previously suggested.

[Blued and Painted]

I see no driveability complaints listed.
Safety loops are installed so it wont eat your package.

Are there other immediate concerns on the car that need attention?
Could the dollars be better spent?

...---...

[AdamIsAdam]

Originally Posted by RocktimusPryme

Maybe its better to have a break point in the rear than the front? In that case yeah the 1350 at the front might be a good idea even if you cant put one in the back. IDK. Seems like it would be better if it failed farther away from the driver.

Yes, I feel that way too. If it breaks in the rear, it seems to be that any damage to the floor would happen after my a$$ Plus, I would think with two drive shaft loops, I'd have a better chance of the shaft just coming out and being left behind as opposed to the front joint breaking and it still being attached to the rear. In that case, the shaft stays with the car doing more damage.

Originally Posted by Blued and Painted

I see no driveability complaints listed.

There are no driveability complaints currently. This is all "while I'm in there" sort of thinking. The car is being worked on for other stuff (fuel system upgrade) and I'm just being proactive as I prepare it for a trip to the track this year. Plus, doing work on the rear will not hinder any other work. It's not either/or.

[AdamIsAdam]

Originally Posted by AG

A 1330 joint has a 1.062" diameter, 1350 is 1.188" and a 3R is 1.125".

I see what you were saying, the 3R size is between 1330 and 1350 and assumed to be proportionally as strong.

So how does this sound:

I buy a new tranny yoke in 1350.
Keep diff yoke of 3R.
Have driveshaft made with 1350 up front and 3R in the rear.

If that's correct, then the only questions left are: 3" or 3.5" steel? Or 3.5" aluminum driveshaft?


Then use a U-joint like this one?
http://www.jegs.com/i/Lakewood/620/23011/10002/-1

[craigs69]

Originally Posted by AdamIsAdam

I see what you were saying, the 3R size is between 1330 and 1350 and assumed to be proportionally as strong.

So how does this sound:

I buy a new tranny yoke in 1350.
Keep diff yoke of 3R.
Have driveshaft made with 1350 up front and 3R in the rear.

If that's correct, then the only questions left are: 3" or 3.5" steel? Or 3.5" aluminum driveshaft?


Then use a U-joint like this one?
http://www.jegs.com/i/Lakewood/620/23011/10002/-1

Adam, I would call one of reputable guys who build driveshafts for a living and get their input on u-joint selction. I believe the driveshaft diameter may be more of a function of length. I know that Denny's bumped me up to a 3.5" due to it being over 50" center to center.

[surfsama]

Originally Posted by AdamIsAdam

If that's correct, then the only questions left are: 3" or 3.5" steel? Or 3.5" aluminum driveshaft?

Your driveshaft critical speed plays a part in this question.

According to this Mark Williams website, the critical RPM speed for 3.0 mild steel 54 inch driveshaft is 5856.

Same length 4130 steel at 3.5 it becomes: 6894

http://www.markwilliams.com/driveshafttech.aspx

[AdamIsAdam]

I had been calling around to shops to inquire about turnaround times, yoke size availability, etc, and this is where I'm at:

Strange Engineering doesn't make anything but 1350, so they are out. Edwin explained that there are two different 1330s, one seems to be the 1.125" BOP 3R plus the traditional 1330. He suggested I speak with The Driveshaft Shop in NC and/or Precision Shaft Technologies in FL. Precision is closed for the day. I also called the shop in Deer Park who mostly wanted me to bring the diff yoke in so he can see it and just make whatever I need out of steel for $325 or so.

The Driveshaft Shop was very patient and sent a lot of emails back and forth. In the end, they suggested that I go with a 3.5" aluminum shaft. He said use 3.5" over 3" due to length, and aluminum since it will twist 20% versus steel only twisting 5-7%, which will absorb some of the torque shock and help soften the blow to the rear end. He can make it with 1350 on the front of the driveshaft and a 3R rear driveshaft yoke with solid u-joints. He will include a billet 1350 trans yoke, all in for $550. Worst part is that the lead time is 2-3 weeks

Richie asked me to make some calls so I'll run this all by him and see what he thinks. Hopefully, we'll be ordering parts on Monday!

[Skip Fix]

79 Camaro project had a 3r-1350 joint in it to drive car around the shop until I recently pulled the SBC and 4 speed out of it.

[Scarebird]

Shaftmasters made my aluminum piece - works nice

http://www.ebay.com/itm/Aluminum-Dri...dWE9gr&vxp=mtr

[David Jones]

Precision Shaft in Tampa has a 2 day turn around. I got my 3.5 aluminum from them a few years ago. So far so good.
$399