Most drop spindles are -2.5" but he could have done springs also......take a look at a stock truck to get an idea. looks to me to be 2.5" spindles with -2" springs....just a guess though
this is how my truck sat with stock springs and no spindles with 235/70 r15's,,,,,,
http://kieth.smugmug.com/Trucks/66-G...0886&k=HQRtBqz
here it is with 255/65 r17's after installing 2.5" drop spindles (air bags on the back)
http://kieth.smugmug.com/Trucks/66-G...4967&k=RGs9Wb7