http://dynatrac.com/pdfs/Choosing_th...using_revC.pdf

That diagram shows it perfectly. By measuring the flange you can easily determine the caster angle. Remember to account for any angle deviation of the surface of your garage floor.

With a stock housing with 5* of caster your pinion would be UP 1* (from level).

It's very common for us to hear that PR44 Unlimited users with lifts feel their rigs drive better than stock (no lift) once they install the new housing. 5-7* of caster is common and drives very well. Users of AEV drop brackets end up with 8* and feel it drives great too.

 

yup I love my unlimited, the jeep tracks super well with the extra caster

 

Will going to an aftermath front drive shaft allow me to run higher caster numbers without damage

 

No. The pinion angle required for an aftermarket driveshaft is radically different than that required by the abysmal factory driveshafts. The factory Jeep axle has a 6 degree spread between pinion and caster. Dynatracs Unlimited replacement axle housing has 10 degrees separation. It seems that D60 front axles are usually set up with 12-13 degrees of separation.

I just replaced all the factory brackets (all really thin shitty material) after the metal on the track bar bracket fatigued and broke off the axle. When I did this I had the knuckles broken free, rolled and rewelded so I have 12 degrees of separation. I don't think the factory spec of 4 degrees is enough caster. I dropped my front DS for repairs and while it was at the shop experimented with 6 and 7 degrees caster and both were a substantial improvement in handling. That kind of caster can't be run with a factory axle and aftermarket driveshafts as the u-joints will run rough as a Cobb and you will be miserable running down the freeway.

Once I get my Jeep back from getting the LS3 installed I plan on adjusting the caster to 7 with a pinion angle of 5.

A Harbor Freight digital angle finder can be used to find the angles.