help with 2003 7.3 Cube

[6foot9]

I have a 2003 7.3 PSD cube box van with 191000. Had some injector noise and put new injector in (Hasco from my Ford dealer). It took care of the noise. The mechanic said that the cylinder where he changed the injector was running cool (he could place his hand on it and leave it there) He said the temperature on it and another on on the front was running about 160 degrees and the others were running 211 to 216. It does not have a lot of power at take off but will cruise at 70 to 85mph with no problems. Should there be concern with the two cylinders that running cooler? Also, I do not have any idea how he got his temperature readings. He seemed to think that it could be a broken ring. He suggested that I drive it for 1000 miles and see it there is a power loss. Also the cubes are heavy, should I be concerned with the lack of power (what I consider lack of power) at takeoff? Thanks in advance.