[core]

The 727 tranny that I am using came with a yoke for 2 1/8" u-joint. The company that is going to make my new driveshaft said that the u-joints for this style yoke would not hold up to 450 horsepower.
He had a new larger yoke that I bought, but the spline cut are different. I have been trying to find the same yoke with the same style splint, but i'm having no luck.
Has anyone used a smaller yoke with around 450 HP and had no problems or do I need to look more for a stronger one?

 

[dana44]

Match the U-joint size you have for the rear end. Sounds like the yoke you have is for a manual transmission, the 727 and 904 use the same yoke. Given you aren't intending to race this car, I don't think you will have a problem with the yoke, but if you do, upgrade later at this point. So, if your rear end yoke is the larger of the two U-joint sizes, then upgrade the trans yoke at the same time.

 

[core]

dana44
the rear u-joint is larger. So to keep the joints the same I should try to find a larger yoke with a spline that will match the tranny? If 904 yokes are the same ill look at them as well.
would you know of a good place to start the search?

 

[CudaPete]

I believe all SB V8's transmissions used the same small u-joint. Some of the big blocks got the large u-joint.

 

[dana44]

A salvage yard is the best place to find one inexpensively. The measurement you want is to measure the rear end yoke size, between the machined locations or inside the tabs on the yoke if it has them, otherwise there will be smooth grooves on the inside the U-joint clips will fit. Same thing for the transmission yoke you locate, measure where the clips are. They are pretty easy to take apart with a screwdriver (flat tipped) and a hammer. Remove the clips, hit against the yoke part the cap sticks in, the cap will pop out the side, flip it over and tap the other side out, then the U-joint will come out. Start looking at the trucks section with a V8, best chance of getting the large U-joint.

 

[core]

It turned out that the rear yoke was compatible with the tranny yoke that I had already. Also was able to customize the driveshaft that I took out of the valiant. Thanks for the help

 

[dana44]

Saves you a bit of money.