The camshaft and ancillary parts are the driving force for engine power; opening and closing the valves at the optimum time and for the longest duration possible, delivering both maximum BHP (brake horsepower) and torque, without one being extended to the detriment of the other.
If the camshaft lobes are worn, then the valves cannot open and close at the parameters set by the engineers who first developed the engine. Equally if the valves do not seat correctly, due to weakened valve-springs or valve seat erosion then a loss of performance will be experienced.
So, when overhauling the valve train, pay particular attention to these potential areas of wear. Renewing the valves, valve springs and possibly the cam-shafts would ensure no wear in these critical areas.
Other parts listed below you may wish to consider:
Replacing as many of the wear prone parts as you can afford will bring performance levels back up to the factory specs. Add as many parts as you wish to the same shopping cart, new valve stem oil seals 0928905015 and cotters 1293224400 for example, and still only pay the same single fixed price shipping cost.