LaTeX: how to change indentation of chapter and sections in report document class?

It seems like relative to the paragraph text, the chapter and section titles have a default indentation that I'd like to manually set. Is there a way to do this using

\setlength{\...}{}

? I'd rather not mess with \titlesec since I've got multiple files and using titlesec previously messed up with my formatting.

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Welcome to TeX.sx! A tip: You can use backticks ` to mark your inline code as I did in my edit. Can you complete your code snippet to an minimal working example (MWE)? –  Kurt Nov 18 '12 at 20:26
Please don't cross-post on Stack Overflow and here, at least not without disclosure. Many *TeX question get migrated here from SO at any rate, as is the case with your question: tex.stackexchange.com/q/83250 –  doncherry Nov 18 '12 at 21:42

There isn't a predefined length for this in the standard classes but it is easy to copy the definitions from report.cls and add some leftskip:

\documentclass{report}

\begin{document}

\section{aaaaa}

aaaa

\makeatletter

\renewcommand\section{\@startsection {section}{1}{\z@}%
{-3.5ex \@plus -1ex \@minus -.2ex}%
{2.3ex \@plus.2ex}%
{\leftskip1in \normalfont\Large\bfseries}}

\makeatother

\section{aaaaa}

aaaa

\end{document}

Note as shown in the section 0.1 example the default indentation is zero.

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