I’ve ridden near those speeds (4:58, 199w NP, 189w average) at 6ft and 190lbs for a flat Ironman. I would guess there are some pretty solid aero gains to be had for you as well as getting closer to 85% FTP for a 70.3. I can guarantee that 60lbs off my body would earn me significant time, even without getting shorter. ;)
I’m also in agreement with the camp that 85% of FTP is achievable. I’m not going to argue about what FTP is or isn’t… but it’s definitely not 85% of 95% of a full gas 20 minute climb PR, so if you’re not fully realistic about that stuff, it’s possible that your 78% is actually close to the 85%. If not, those ~12w or so should be enough to get you close to <2:20 from your current stats. I believe 85% to be pretty achievable with a good run to follow for most athletes riding under 2:30 for a 70.3.
I’m also in agreement with the camp that 85% of FTP is achievable. I’m not going to argue about what FTP is or isn’t… but it’s definitely not 85% of 95% of a full gas 20 minute climb PR, so if you’re not fully realistic about that stuff, it’s possible that your 78% is actually close to the 85%. If not, those ~12w or so should be enough to get you close to <2:20 from your current stats. I believe 85% to be pretty achievable with a good run to follow for most athletes riding under 2:30 for a 70.3.