Reduction in Piston Engine Horsepower due to High Temperature

[orionsbelt]

Hi Chaps

Can you please direct to a source of data relating to the Engine performance of Lycoming 0235/0320/0360 or other light aircraft engines at very high surface temperature say above 25 deg c?(My 0320 manual has no info on this topic)
Over the last few days at these high temperature its like taking off with the Carb Ht selected to hot.
I have managed to Search PPrune and come up with a WW2 dated paper but that’s all.
Are there any more relevant up to date papers on the subject?
While Aircraft Manuals and AIC 67/2002 do give performance corrections for temperature they do not quantify the horsepower reduction at high temperatures.

Thanks Orion