what would the highest temp i should allow for my lrp 28 spec 3

after the break-in no more than 270F

just like every engine...some say no more than 240, no more than 260 and so on...i say somewhere between 240-280 is the safe range

generally i would say don't worry about temps as every engine is different, and there are to many variables, temp is not a very accurate tuning tool, performance and smoke trail are much better indicators, but i would say no more then 300 F under normal running conditions if you must have a temp.

aslong as you keep it under 300 its ok

during break in it should be from 200-220.