I had just read a post that indicates that i have to use the stock balancer with an underdrive pulley. I thought the pulley served as the balancer also. If i have to use the stock balancer too then how does this underdrive pulley fit on there?? Its the motorvation pulley from Summit Racing.

 

You double them up, the underdrive pulley mounts closest to the block with the stock pulley/balancer mounted in front of it. The pulley should have come with longer bolts.

 

as already stated. they go together

there are some underdrive pulleys that act as a balancer but the only ones that come to mind are ASP pulleys'