The title says it all, but I am repeating it here. Here is the sentence.
I looked upon them for inspiration.
Is this grammatically correct ? Is there a better alternative ?
The prepositions here are tricky and, even as a native English speaker, I don’t see any logic to them.
“I looked to them for inspiration.”
means they were my source of inspiration.
“I looked upon them as inspiration.”
means I classified them as inspiration (maybe not for me).
“I looked upon them for inspiration.”
is a slightly archaic way of saying that the reason I looked at them (literally, with my eyes) was to get inspiration.
Look on/upon someone - Both mean the same! In the example that you have quoted, wrt the context, I would say, 'I looked upon them for inspiration' simply means that you looked for inspiration in them. When you say, 'I look to them for inspiration', it means almost the same. Here, it sounds like When you need inspiration you look to them. The stress is on 'when you need' I could be wrong.