727 Tail Measurement....

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pastortom1

pastortom1

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Guys........

Can anyone tell me what the correct measurement would be from the actual end of the tailshaft housing to the center of the front U-Cap??

Mine seems to be sticking out too far....just don't seem right.......I notice a bit of "play" as well there when I push up on the driveshaft......Funny, but then not.... I just had the U-joints changed at our "Pro-Shop", but they failed to mention the play in the shaft......I'd guess I have at least a 1/8" slop inside the tailshaft, maybe 3/16" when I push up on the driveshaft....I would guess this slop could be related to the possibility that the driveshaft may not be fully inserted into the tail housing.......or am I all wet? Does this look like it's in all the way (normal distance), or not? Is my slop a tail bearing or something, or does this have to go in farther? I don't do much work in this area, so give me some input.........I know the thing still vibrates under acceleration.....probably right there is the culprit....but what's the problem?

I stated earlier that they shortened this driveshaft........Looks a little too short to me..........What say ye?

110_1023.jpg
 
Me thinks you're right, looks too short. I'm not at home to measure but I know from mocking up my street rod project about an inch was the goal as I recall.
 
No doubt about it. That is not in far enough and if you keep driving it, you will have to replace the tail shaft bushing in the tranny if you don't have to already. There should only be 3/4 to 1 inch sticking out of the tranny.

Jack
 
That's what I thought Jack........It just didn't look correct........

The guys who set up this drivetrain had the shaft shortened, and just plain went too far.........This thing is only 45.75" center to center on the caps.........AMAZING.

Well, now I need to buy an A-Body driveshaft that will work here..........it will probably have to be shortened due to the 727, but I have no choice I guess...........

If you guys can hook me up with one, get back to me..........:read2:
 
Don't look far enough in to me either but if your pic is with it hanging in the air such as when it's on a lift it could possibly be farther out than when it's setting on the ground. As the rearend moves up and down when you drive the car the yoke slides in and out. The proper position is when you have the weight on the rear tires so it's setting at it's normal stance and you unbolt the driveshaft from the rear you should be able to slide it in and out of the trans. 1"

You don't necessarily have to have a driveshaft shortened. There were lots of A-bodies with 727 transmissions. You just need a shaft from a A-body with a 727 trans. and what ever rearend you have.

BTW: don't drive it until you know it's right. It can do alot more damage than just wearing out the extension housing bushing. Back when I was a kid I had one snap the extension housing in half.
 
For a dart A body, not a valiant right? The Dart is a little longer A body. I have a shaft out of a Dart with a 727 and an 8 3/4 can sell you. It is the standard size small u-joint type. I would have new joints put in it and rebalance, also check the fit too in your ride before and if you need to cut it.

PS way to short, guys are correct, you need about 1" - 3/4" for travel on bumps etc.
 
fishy68 said:
Don't look far enough in to me either but if your pic is with it hanging in the air such as when it's on a lift it could possibly be farther out than when it's setting on the ground. As the rearend moves up and down when you drive the car the yoke slides in and out. The proper position is when you have the weight on the rear tires so it's setting at it's normal stance and you unbolt the driveshaft from the rear you should be able to slide it in and out of the trans. 1"

You don't necessarily have to have a driveshaft shortened. There were lots of A-bodies with 727 transmissions. You just need a shaft from a A-body with a 727 trans. and what ever rearend you have.

BTW: don't drive it until you know it's right. It can do alot more damage than just wearing out the extension housing bushing. Back when I was a kid I had one snap the extension housing in half.
Click to expand...

there is only only one tail shaft for passenger cars...whether it is an A/b/c/d/e/f/g bodies cars....only the pickup trucks were available with a shorten tail shaft...

i have taken the same 727 out of e body and put it in an a body....
 
70aarcuda said:
there is only only one tail shaft for passenger cars...whether it is an A/b/c/d/e/f/g bodies cars....only the pickup trucks were available with a shorten tail shaft...

i have taken the same 727 out of e body and put it in an a body....
Click to expand...

Yes you are correct. I think you may have misunderstood me. I said there were lots of A-bodies built using the 727 trans. Not there are lots of different 727 transmissions.
 
What I have is a 74 Dart Sport..........727 to an 8-1/4 rear....the car decodes to a 318, which I assume had a 904.........So, they shortened the shaft, but went too far.

The picture I took is with the weight on the rear wheels, and the front jacked under the K-Frame just enough for me to slide under and tinker.

I have had one guy tell me that their driveshaft ran appx. 47.75 or a little longer for their 727 on this body..........makes sense........that shaft would be a nearly perfect fit on this car........

"Measure twice, cut once" wasn't the rule with my shaft.......they butchered it.

What other measurements do I need to take to be certain of the shaft I need?..............I think it's obvious, but chime in so I'm confident about it...........:read2:
 
The best way to do it is to slide the yoke into the tranny to the position that you want it. Then measure from the center of your rearend yoke where the u-joint mounts, (This would be where the bolt holes are), forward to the center of the yoke where your u-joint caps are. I think I said that right. Clear as mud?

Jack
 
No, that's plain enough.........What about the yoke's? Are they all the same for a 727 and 8-1/4 rear?

In my understanding, there were 3 sizes (maybe 4, like a super light duty)..........

I don't think the 904 yokes are the same size as the 727's, and then the Dana's are even larger I believe...........

Are there more than one for the 727's with an 8-1/4? :read2:
 
The 904 and 727 yokes are different. I believe that the rear yokes only came stock in 2 sizes. I know my 7 1/4 rear yoke is the same as the small 8 3/4 yoke as far as u-joint cup size.

Jack
 
+Well, I guess the easiest way to handle this will be to take the car to Central Florida Driveshaft and have it done right the first time (relatively speaking).

Using my existing yokes and putting on a correct tube will probably be best, and it'll be balanced too.

8)
 
pastortom1 said:
+Well, I guess the easiest way to handle this will be to take the car to Central Florida Driveshaft and have it done right the first time (relatively speaking).

Using my existing yokes and putting on a correct tube will probably be best, and it'll be balanced too.

8)
Click to expand...

That's probably your best bet. Sure wouldn't take it back to the other guys. They might cut it even shorter yet.:scratch:
 
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