The 2005 GMC Sierra-2500HD has 16 valves.
The 2005 GMC Savana has 12 valves.
The 2005 GMC Canyon has 16 valves.
The 2005 GMC Yukon has 16 valves.
The 2005 GMC Savana-Cargo has 12 valves.
The 2005 GMC Yukon-XL has 16 valves.
The 2005 GMC Sierra-1500 has 12 valves.
The 2005 GMC Yukon has overhead valves (OHV).
The 2005 GMC Savana has overhead valves (OHV).
It's worth about $13,000. See quotes at http://www.edmunds.com/gmc/sierra2500hd/2006/index.html
The 2005 GMC Savana-Cargo has overhead valves (OHV).
The 2005 GMC Sierra-1500 has overhead valves (OHV).
The 2005 GMC Yukon-XL has overhead valves (OHV).