Help identify cannondale bike

[Redwhiteandink]

Hello everyone I purchased this Vintage cannondale for $60 I researched the CC on the bottom it says it’s 1985 here are the pics when i picked it up yesterday and how i fixed it up today. Can you help me with which model it is and how i would restore the black paint on it

 

[black lightning 1987]

That may be an ST400 but it's hard to tell much from the low resolution pictures. I can't see how bad the paint is but black is fairly easy to touch up with a brush and make look presentable. I have sanded, masked, and spray painted single tubes that had more damage.