[wiroto]

I will try to answer your question
Roller lifters are designed to follow a roller cam and the bars are to keep the lifters running parell to each other.Different Manufactures aquire this with different means, most patented,
If you are planning on going to a roller you will nead a complete confersion kit, cam,lifters,pushrods ,Dist gearA new timeing gear set is a good idea at the same time. At this time I would check cam bearings They can tell you a lot about the condition of the other bearings in the engine.
Hope this helps.
wiroto