If you want accurate engine performance fighures, you need to get hold of the engine manual produced by the engine manufacturer and consult the appropriate graphs.
Your friendly maintenance organisation will probably have one since they get a new one with each new/ manufacturer overhauled engine or contact Lycoming direct.
Note that Lycoming will only deal with engine output, it will not make any allowances for the actual aircraft instalation or the propeller used.
Regards,
DFC