Is it only half we buying or is it both sides of the block?

Our Roller Rockers kits definitely come complete to do both cylinder heads, not just one, as the photos in the ad may suggest. you may get more information by the link given below:

http://www.maceengineering.com.au/HIGH-RATIO-ROLLER-ROCKERS-FOR-HOLDEN-ECOTEC-AND-L67-V6