Keep looking.. here is a section from the yet to be released tech tip on this axle swap:
The P-30's come with a variety of axle set ups. I have seen all of the following on P-30 chassis, or on chassis very similar to (I did not read all the tags):
• A -- 5-lug front 10-lug rear I-beam front, Dana 70HD, Dana 80, or Rockwell rear.
• B -- 5-lug front independent suspension, 10-lug rear, similar rear choices as above.
• C -- 8-lug front and rear with I-beam front, very few of these, and probably Dana 70, 70HD, or a 14-bolt rear.
• D -- 8-lug front and rear with independent front suspension (one of the most common 8-lug P-30 chassis) and probably the same rear axle choices as the I-beam front axle version.
The one of interest for an AD 1.5 or 2 ton is Choice A -- an I-beam front with 5 lugs and a Dana rear with 10 lugs. The Rockwell is not such a good choice as fast gears are either not available ever, or hard to get/expensive. You can quickly spot a Rockwell by the square axle "tubes."
The 5/10-lug axle pairs should have disc brakes all the way around, as I have not seen them any other way (other than our antique trucks). These axle combinations come from trucks with an approximate 14,000 lb GVW, so more than your 1.5 ton AD, and slightly less than your 2 ton AD truck. Here is an example of axles ready to be installed, note the large disc brakes front and rear:
http://rides.webshots.com/photo/1484193568080251109uMNsAt Grigg
