Alright, so... I was messing with the AC2 codes in brotherhood and found that the infinite health code is pretty much the same. I just kept cutting off the end of the original code until I found a match. I haven't noticed any glitches, so enjoy.
80 1F 00 58 7F C3 F3 78 90 09
60 00 00 00 7F C3 F3 78 90 09
Credits go to xtatu for posting the original Assassins Creed 2 code
Edit: Extremely high falls and heavy weapons still seem to be able to kill you, if you're careless. Pretty much identical to how it works in Assassins Creed 2.