Hackin' on yhe drive shaft

[5th_Ave_Sleeper]

I switched from a 904 to a 727 tranny and from a 7.25 to a 8.25 rear end in the ole' 5th Ave. Now I must get a drive shaft made.
My question is: How far out of the tailshaft should i stick the yoke to get my measurement?
Ive heard anywhere from 1/2" to 2" from different people. Isnt it a matter of suspension travel?
I know bad things can happen if the yoke keeps smashing into the back of the tranny
Thanks for any helpy all can throw at me

[1972roadrunner]

? don't know... experiment hook up the pinion yoke on the rearend and have somebody jump in the trunk while your underneath measureing how far the thing moves...

maybe it'd be sumthin like this...

" ooh! aah! ow! oof! 1 ooh! and ow! 1/ aah! 2 inches oww!! STOP!!!! oof! ok ok, 1 and 1/2 inches! oh my head....."

hahahaha! only playin! seriously though, i'm not sure... do you want me to measure mine from yoke to yoke?

[cuda66273]

The correct way to measure a driveline is:

From the flat surface of the rear U-joint face to:
1. the end of the output shaft.
2. the face of the tailshaft housing

These dimensions should be taken with the car at ride hiegth. Most good Drive line builders will require both of these numbers.

Have a look here:

http://www.dennysdriveshaft.com

[5th_Ave_Sleeper]

cuda66273, I dont understand

[rb77413]

What I did was measure from the flat of the u joint on the rear end. Pinon, to the rear seal on the tranny with the car jacked up by the rear axle and level. This is how the driveshaft told me how to measure it. Since this was my second 'shaft I took to them

[cuda66273]

Here's a more direct link
http://www.dennysdriveshaft.com/html/b.html

[5thAve]

From what I remember there should be about 1 1/2" of play in the tranny yoke so it won't bottom out. If you're not going to keep your back end raised up the way it is now deal with it before you get the shaft cut/made, unless of course you want to do it twice (lowering the rear will make the shaft too long).

If you want I can measure how long my driveshaft is- same setup as you've got and I've got the stock driveshaft for that setup on there.

[5th_Ave_Sleeper]

5thAve, did the dippy copcars come with 727/8.25 combo? If so i know where one is. and a rear end that fits And antisway bars
5th

[5thAve]

Some came with a 904, some with a 727. Easiest way to tell is to look on the passenger side of the pan for that bulge.

The rear is more then likely an 8 1/4 in that Dip. If you've got the 4 leaf springs grab the 5/6 leafers from it while you're at it and also grab the front sway bar- having one in the back and not the bigger one in the front is the opposite of not having a back one at all.

Guess it's too late, since you've got the van rear in there already, but when I put the 8 1/4 in I did it without disconnecting the shocks and parking brake and without taking the back brakes apart. Made it real simple The stock M 8 1/4 is an inch or two NARROWER then the 7 1/4.

[5th_Ave_Sleeper]

5thAve, yes, if you could measure your driveshaft from U-joint center to U-joint center, that would be great!
I am definatly getting ALL the suspension parts from the dippy cop including the rearend. this one is just a bit too hoakey

[dewme5]

one guy is giving you the answer, and another guy is giving you an opinion? why don't you call the driveshaft shop that is going to do the work, and ask them how they want it measured? and, don't try to do it at home.

[5th_Ave_Sleeper]

Good point
5th

[Reggie]

Grab ALL of the cop car sway bar hardware too.

[5thAve]

Driveshaft length can vary depending on who you're talking to. I had thought the best way is to measure when you're having one made is to go from the rear pinion where the u-joint goes to where the u-joint would be in the transmission yoke with the yoke bottomed out in the tranny, and then subtracting the 1 1/2" (or whatever that measurement actually is) for your clearance. Never had a drivesaft made tho.


Get that other rear end in there, and try whatever way turns out the way they want to measure the driveshaft. I'll measure mine and see how close your # is to the one the factory went by for their fleet cars Maybe you'll get lucky and that Dip will have a 727 and you'll score the proper driveshaft too! Don't forget to grab the speedo gear from the tranny while you're getting the other parts, and the cop speedometer from the dash if it has it.

[5th_Ave_Sleeper]

Got the copper speedo! took it apart and Zeroed it out. might as well, the whole drive train has been replaced. I'll get a speedo gear from my local dodge dealer when all else is done. I still need to cut a hole in the floor and in stall a floor shifter I am missing some important parts for the colum shift linkage
5th

[1972roadrunner]

cut a hole?? all you need is a hole large enuff for a cable to slip through...then drill some more holes and bolt a floor shifter to the floor... maybe a quicksilver would look good...

nice huh? if anything happens to mine, this is what i want

[cuda66273]

???? there is no important parts for a colum shifter