'72 C10 Suspension Q's

I'm currently starting work on a 1972 C-10. It's somewhat rough, but nothing too intimidating.

My root questions lie in the area of suspension--I'm not a guy too experienced with truck or towing suspension.

My wants are:

Lowered about 5" front and back. I have no problem rewelding mounts, etc.

My need is: That I'd like to still be able to tow with it from time to time. I recently sold my '96 Dodge 3500 Cummins, but still have a light trailer and race car that I'd like to tow to the track. The car and trailer together weigh in at around 4500lbs. (open deck trailer).

What I was looking at was the rear air bag suspension setup from "Early Classic Restoration and Suspension". This *seems* to be the setup that I should use, however, I was wondering if anyone else might have a better solution or any feedback on such a setup.

Thanks in advance for any insight.

I also have a 72 C 10 that has had damn near everything replaced on it now. I never lowered mine, but I think I can lend some help with your dilema.
But first off, is is a coil or leaf rear on yours?
If it's a leaf rear, then you will need a flip shackle kit to mount your diff on top of your leafs instead of underneath. Along with this you will need to C notch the frame to get 5" of lowering plus you need to install an adjustable pan hard bar.
If it's coil, you can buy 5" lowering coils to lower it. You will still need the adjustable panhard for this as well.

On the front, you will need drop coils and drop spindles. I believe the largest drop coils you can get for the front is 3" and then you will need a pair of 2" drop spindles.
You can find these parts at www.gmcpauls.com , or www.classicheartbeat.com . But seeing how you are in Philly, GMC Pauls would be closer. Early Classic Enterprises will have them as well.

Hope this helps