[ercoupe-tech] c-75 to c-85

[nick.king88]

What turns a 75 into a 85. If I understand, it is just mods. My log books make 
reference to my C-85 , but also mentions theC-75. The plate on the motor says 
75.
  I need to know so I know what rpm to cruise at. I have a 50 pitch prop. Also 
, my header tank leaks (cracked at bend in rear)How do I remove it.