Cambiar limite de lineas en entradas de mi blog

<?php get_header(); ?>

	<div id="content">

	<?php if (have_posts()) : ?>

		<?php while (have_posts()) : the_post(); ?>

			<div class="post" id="post-<?php the_ID(); ?>">
				<h2 class="link"><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>
				<div class="top-tools"><?php the_time('F jS, Y') ?></span>    <?php edit_post_link('Edit', '', '  '); ?></div>

				<div class="entry">
				<?php if ( get_post_meta($post->ID, 'thumbnail', true) ) { ?> <br class="clear-fix"/>
				<div class="post-thumbnail"><img src="<?php $key="thumbnail"; echo get_post_meta($post->ID, $key, true); ?>" alt="<?php the_permalink() ?>"/></div>				
				<?php } ?>
					<?php the_excerpt(); ?> 
				
				</div>

				<div class="tools"><div class="float-left"><span>Posted in</span> <?php the_category(', ') ?> </div><div class="float-right"> <?php comments_popup_link('<span>Comments</span> (0)', '<span>Comments</span> (1)', '<span>Comments</span> (%)'); ?></div></div>
			</div>

		<?php endwhile; ?>

		<div class="older-newer">
			<div class="older-left"><?php next_posts_link('Older Entries') ?></div>
			<div class="newer-right"><?php previous_posts_link('Newer Entries') ?></div>
		</div>

	<?php else : ?>

		<h1 class="center">Not Found</h1>
		<p class="center">Sorry, but you are looking for something that isn't here.</p>
		<?php include (TEMPLATEPATH . "/searchform.php"); ?>

	<?php endif; ?>

	</div>

<?php get_sidebar(); ?>

<?php get_footer(); ?>

<a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>">Read more</a>

    function new_excerpt_length($length) {
        return 300;
    }
    add_filter('excerpt_length', 'new_excerpt_length');

function wp_trim_excerpt($text) {
	$raw_excerpt = $text;
	if ( '' == $text ) {
		$text = get_the_content('');

		$text = strip_shortcodes( $text );

		$text = apply_filters('the_content', $text);
		$text = str_replace(']]>', ']]>', $text);
		$text = strip_tags($text);
		$excerpt_length = apply_filters('excerpt_length', 55);
		$excerpt_more = apply_filters('excerpt_more', ' ' . '[...]');
		$words = preg_split("/[\n\r\t ]+/", $text, $excerpt_length + 1, PREG_SPLIT_NO_EMPTY);
		if ( count($words) > $excerpt_length ) {
			array_pop($words);
			$text = implode(' ', $words);
			$text = $text . $excerpt_more;
		} else {
			$text = implode(' ', $words);
		}
	}
	return apply_filters('wp_trim_excerpt', $text, $raw_excerpt);
}

$excerpt_length = apply_filters('excerpt_length', 55);

$excerpt_more = apply_filters('excerpt_more', ' ' . '[...]');