Burntclutch,
I'm not sure why anyone would want to lower a "Stock" truck, or how he would expect to keep it "Stock" when it's been lowered but...
Perhaps you can suggest that your cousin to try some 15 inch radials and such before he starts whacking on it. That will lower it without changing anything, and very simple to put back, if he ever wants to.
My next suggestion would be to change out the springs to a mono-leaf. Again, easily done, and/or put back and not as radical as chopping on a frame.
Or if it's that clean, tell him I'll trade him a nice 52 he can chop on and I'll take his Art-Deco truck.
Lastly, suggest that he go out to E-Bay and see what the "Clean" nice stock Art-Deco trucks are selling for, then ask him if he really wants to lose that much money.
