Brian, The correct limits will be listed on the Type Certificate Data Sheets. You will find that information here:
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/MainFrame?OpenFrameSet It takes awhile to dig this information out, so be patient. No one in a Cessna 150 Users group can tell you that they have the "100% correct" information unless they are quoting the TCDS, but this is what was used when the engine was certified. Kevin