If it started and ran you are not180 out. As the others have stated as long as the dots are actually lined up the cam can be at either 6 or 12. If you are 1 tooth off that can cause power issues. I would double check everything else before taking it back apart.
Verify the timing pointer and damper TDC using a piston stop. Make sure the exhaust is not restricted, etc.
If you have the cam card you can check to be sure you are not a tooth off on the timing chain without taking it apart. Put a dial indicator on #1 intake and rotate the engine. Compare the cam card spec to the actual valve opening.
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