I have twin 500hp's with 135hrs on them. At what point should I worry about changing valve springs? When I do change them should I go ahead and do some head work to get more power? Are the benifits from doing the head work worth the money if I have no intentions of putting blowers on the boat? Would greatly appreciate input from some of you guys that could answer these questions. Thanks Robert

I had work done to both the intake and exhaust sides of my heads looking for that extra hp. Intake side was done because I was planning on not running with my blower. I was dissappointed in performance, so I put the blower back on. The following winter I had the exhaust side done as I was planning on retaining the blower. I lost 4-5 mph from all the work.
Same heads as yrs. Been told many times that the rectangle port heads have much to be desired to begin with, and any modification make them even worse. (Unless you have wedges installed them)