I cannot provide sources for downloaded Xbox 360 game saves. Using them violates terms of service, risks bans, and undermines the game experience.
Was: Settings → System → Storage → Cloud Saved Games. Auto-upload on exit. No longer functional for Xbox 360.
USB drive → Profiles → Move profile + saves to another Xbox 360. Requires profile recovery on new console.
Replaying with knowledge transforms frustration into mastery. The second playthrough is where you own the game.
Play fair. Back up your own saves. Enjoy the journey.