Well I went ahead and got the cast iron manifolds and risers to replace the somewhat rusted ones I have. I guess I was curious if it was benficial to add jumper hose? I understand the way the flow goes through there now, but wasnt sure if there might be benifit to adding those also? I ran a little hot enough to partially burn up internal flapper on starboard(post mereplacing offcourse) . So next move is impellar that hasnt been done in couple years.