According to the marketing group the 06' option will be called VortecMax Performance pack.

 

this is the same info as shown in the autobook we use here at work. the VHO isn't a gm term either. if i recall correctly the commonly called VHO is simply listed as performance package. on the window sticker it is listed as Silverado Performance Edition. the VHO nickname comes from the badging on the side of vortec high output which is based on the engine, not the package. i haven't seen any pictures of the badging on the vortec max.