[Tigers] Aluminum heads recommendations

[Thomas Witt]

Dave,
  Probably the greater advantage of the "roller tip" is it should reduce 
friction at the contact point of the valve.  This should reduce the valve 
side load and increase the life of the valve guide. This can be especially 
helpful in high lift cams or cams that have a fast ramp.

 The reduced friction also likely reduces some power loss and decreases 
heat. To what extent that is beneficial verses the cost is likely up for 
debate.

Tom