The cam timing (the relationship between the cam and the crankshaft) can be used to adjust where max power appears in the engine speed range. This is not a huge range of adjustment however, and your mechanic would need to be careful that there is enough space between open valves and the piston top. The standard arrangement sees the cam timing based on TDC from the factory though the actual position of the cam varies depending upon how much has been cut from the head or block in its lifetime. Shorter the head and block, the closer the cam is to the crank and the shorter the timing chain needs to be. Often people may use an adjustable timing sprocket to ‘lose’ some of this extra timing chain length, more as a way to advance the cam timing back to its standard location.
As for the noise - did your mechanic bleed the air from the hydraulic timing chain tensioner?