yoke help?

[74roadrunner440]

i just swaped out me 8.25 rear end with my freshley rebuilt 8.75 but now my drive shaft u joint is to small i have a 742 case w 323 posi any one now what dimensions should be for the yoke i need or wich yoke i need to find? thanks again every one

 

[Meep-Meep]

I don't know the dimensions off the top of my head but it's possible you have a 7260 U joint and a 7290 yoke. You can get a conversion joint to hook it all up and that will get you down the road. If you plan on a lot of power and abuse then get a new shaft with 7290's.

 

[moparmarks]

With your motor I'd go ahead and have a 7290 joint shaft made.

 

[74roadrunner440]

where do u get a new shaft w the joints

 

[RustyRatRod]

Yeah cause you gotta shorten the drive shaft anyway, right?

 

[74roadrunner440]

no it fits in the yoke just u joint is to short where do u get a new shaft and joints?

 

[RustyRatRod]

I usually do my own drive shaft work. If you have a good miter saw with a metal cutting blade or fiber wheel and you can weld, you can do it yourself. Long as you make straight cuts and weld the yoke on in phase you'll be fine.

 

[Meep-Meep]

Maybe do a search for drive line repair in your area. Surely there must be someone who can retube and balance a drive shaft.

Hey Rusty, how are you dealing with the runout after welding the tube to the yokes? Balancing is required to deal with a manufacturing tolerance issue, but I suppose if you have the two ends at near zero runout, and heat shrink the shaft to make it straight, you can get away without balancing.

 

[RustyRatRod]

I've never had balance problems making straight cuts. Long as the cut is 100% perpendicular to the shaft centerline, the yoke will be straight....and of course phased correctly. There's a good driveline shop in Macon and he laughs when people ask about balancing. It's a family run business. Been there almost 100 years. He showed me how to do it years ago and I ain't ever had a problem.

 

[74roadrunner440]

even if i did weld the yokes on where do i get both ends in a 7290 yokes both the trans side n the dif side with the biger joints ?

 

[RustyRatRod]

Damn if I know. I never mess with the little ones unless I have a functional shaft already. I use the 1350 stuff. Summit sells the weld on 1350 yoke for 21 bucks.

 

[74roadrunner440]

i thought the 7290 were the big one the 7260 are the small ones i have in car now and should i replace the fron joint too

 

[daredevil]

A lot of truck repair shops do driveshafts

 

[RustyRatRod]

Here is a nice read on U joints sizes and nomenclature. Note the 1310 is the same as the 2970 series. The 1350 is two sizes bigger.

http://www.therangerstation.com/Magazine/summer2008/ujoints.htm

 

[Meep-Meep]

My 66 hemi cars are both 4 spds and they have the 1330 U joints. That size is pretty similar to the 7290 but the main difference is where the retaining clips go. The 1330 clips are on the outside and the 7260/90 are on the inside. My 67 Ford with 9" rear also has the 1330 from the factory.

I have a buddy that owns a precision balancing shop in San Jose and that shop was started by his dad and uncle building driveshafts back in 1947. Those guys never balanced a driveshaft as far as I know. They just made them straight with no excessive runout. Probably exactly what you are doing.

 

[74roadrunner440]

but my ? is wich it the best way to go change to 1350 or 7290 or just find the smaller yoke i want the shaft to stand up with the power i have in my engine and should i change the front nuckle also? or just the rear? or just cut n weld a new yoke in?

 

[74roadrunner440]

any one know wich wish u joint uses the small in drive shaft and the big on the yoke for 8.75 ?

 

[RustyRatRod]

I've never seen a factory drive shaft with two different u joint sizes.

 

[74roadrunner440]

they do make them a friend of mine who runs a mopar restoration shop in ohio thats what he had to do on his 69 charger n his 73 charger both w bb 440 w dual quads on it its not a facory thing but make it for the difrent yokes w u have a small on your drive shaft and big yoke on dif

 

[Meep-Meep]

Well, never say never, but I'm with Rusty on the U joint theory. There are conversion joints but I too have never seen one from the factory.

Since you have the big 7290 yoke just have the shaft made accordingly and get a new slip yoke to match.