dana 30 swap

Hey all.  I have a 57 m38a1.  I got a dauntless in it, power steering, a bunch of goodies.  I am swaping out the dana 25 for a 30.  I got it all set and ready to go in.  The 30 is from a 73 cj5 and I swapped knuckes, hubs, spindles and even an axleshaft from an even later cj with disc brakes. Anyways, my question is, has anyone swapped a dana 30 into a pre 72 jeep?  I probably need a new driveshaft but I'm not sure.  More importantly tho, do I need shims to rotate the pinion?  Or should it just bolt right in?  Thank you so much, I wanna get this in soon.  It's been a long time in the making.  

It really depends on your suspension height and drivetrain angle.

The caster setting is fixed by the perch and the pinion angle is relative to the caster angle and can't be changed without cutting off and repositioning the knuckles.

The pinion angle is more important than your caster angle and takes precedence. But that is not to say the caster isn't important. It's just to say you'll be compromising one for the other.

So, in order to have a pinion angle that doesn't over extend the u-joint and not be a vibration nuisance, you can set your caster with shims. The caster will help the hi-speed road feel. As your caster decreases, the rig will feel lighter in the front end. The greater your suspension height, the more the pinion angle will need to be adjusted, again with shims, and that will also affect the caster.

It will be a compromise.

If starting from the beginning, you'd set the knuckle with regard to suspension height to acheive the right pinion angle, and then set the perches with regard to caster.  

so what values should I be looking for, in regards to a pinion angle?    Thanks for your help.  

i have my 70 potal(frame and suspention is identical to a CJ5) jeep's  caster set at about 3 degrees and it seems to handle fine but im also running 35" tires and from what was explaned to me is the bigger your tires the less caster thats required, im not sure how much of an angle is too much for the penion, if you go too high of an angle than your penion bearings wont get enough lubercation but as long as you dont have a massave lift i dont think its to big of a deal. if its a minimal lift than just try to get the penion relitavly lined up with your t-case

hey ftgiles does this sound about right or am i way off?  

Just mount it on the springs and take some measurements with your angle/protractor gauge with the weight of the jeep sitting on the suspension.

The pinion should be parallel to the x-case output. That makes the u-joint angle on both ends of the driveshaft the same. That's what is required for a vibration free setup. It would be nice if that angle was less than 12-15 degrees. Then let the suspension fully droop to the point that your shocks will allow and then check to see if the u-joints are binding.

Then, see what kind of caster angle you're left with. Nice would be 4 degrees for 35" tires, 5 degrees for 33's, and 6 degrees for 31's.