Jim -- I'll bet you do just fine.  Blake F. Donaldson MD placed ill/fat 
people on all meat with sufficient fat and nothing else but water and 
optional coffee for months with great success.  By sufficient fat -- he 
used the proportion of 6 oz lean meat with 2 oz of fat. He did not use the 
additional minerals or salt Phinney used and his ill/fat patients regained 
there health.  You are already normal weight, healthy and athletic -- so I 
cannot believe that an all meat/fat diet would harm you.  Your activity 
level may demand longer period of adaptation for utilizing fat for energy 
and you may need more calories.   All Phinney says about the excessive 
protein is that "it has the potential for negative side-effects if intake 
of this nutrient exceeds 25% of daily energy expenditure."  This is 
impossible if you always eat sufficient fat because fat contains more 
calories than protein.  So if you feel weak/fatigued, just eat more meat 
with proper fat. Can't wait until you post your results -- should be 
fascinating.