Working on Ryan's 72 dart. He is going to order a new drive shaft for it. The one he has is damaged and bent so he wants to upgrade now. I have a couple questions:

1) Car has had a vibration in the past. I thought maybe that the yoke was not slid up inside the tranny far enough. So last week we installed the transmission that we just rebuilt. When installing the drive shaft I slid the front yoke in as far as it would go. It actually went in and got tight so I am guessing I was at the end of the spline. It looks as though it could go in another 1" but it was tight so I didn't force it. So I put the rear u-joint in the saddle and that only pulled the shaft out about 1". 1" out should be Ok according to what I'm reading, correct?

Do they make different front yokes with longer splines? I just want to make sure we have enough spline engagement.

2) Rear end yoke - The u-joint caps do not fit snug in the yoke saddles. There is at least a 1/16" maybe a little more of movement between the saddles and the u-joint cap clips. I know that this should not be and was probably adding to the vibration issue. Anyway, Ryan would like to upgrade to the larger U-joints now while he is getting the new drive shaft. His rear is a 489 case. Are all 489 case pinions the same spline or do I need to pull the yoke off to see.

3) Any reason to go to the 1350 size joints or should the 7290 joints do the trick. For those who don't know it is a 3300# car with a 4-speed OD transmission, running 4.30 gears and slicks. He hopes to hit high 12's with this car and his nitrous bottles.

Any help and opinions are greatly appreciated. Also any good places to get the new yokes would be appreciated greatly. Mancini?

Thanks,
Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Sounds like you're trying to put a 7260 u-joint in a 7290 rear yoke. The 7260 is the standard Slant/small block u-joint and is plenty strong for a 12 second car.

I wouldn't bother with the 1350 u-joint unless you already have the yokes for them.

Yes, there are different length trans yokes, but all of them should have the same length splines. 3/4"-1" from bottomed out in the tailshaft is enough free play. More than that is hard on the tailshaft bushing, less will break something.

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Official Cookie and Mater Tormentor.

I will have to look up the width for the 7290 joint and measure the yoke.

Thanks,

Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6