I don't have any connection with the stuff other than I researched it some. Heck, you take a turd and call it "new" and I'll buy it. Anyway, after being confused by the fact that you measured your engine displacement in inches and your temperature in centegrade...I have found one thing that worked for me. I run a mixture of 50/50 which all research I have done is supposed to be the best (water transferes (releases) heat much more efficiently than
antifreeze).. I was normally running 180-200 (F) on my 289 (up to 210 on a hot day). I added one bottle of RMI-25 Cooling System Treatment (8 Fl. ozs) or 236.6ML. Anyway, on the hottest day now it runs consistently 15 degrees (F) cooler and I mean ALWAYS. This stuff really works. I run Evans Coolant (100%) in my hotrod which will heat the same but can not boil over. Good luck