Editing style of posts pages

[francis1tree]

Hi I have come across a problem in that the site I have created for a client has got bigger and bigger and is now over 450 pages. It is getting slower and slower to edit/add new pages (although the public site is performing fine) and I have been told that WP cannot handle sites this large built using 'pages' as opposed to 'posts'; and I will need to create new pages from now on as 'posts'. This is going to be awkward as there are several different templates/page styles. To start with I need to get into the styling for the posts pages to remove all the info. about "Posted by..." etc. How do I do this and what is the template that handles the onpage content of posts? All I can find is

page_blog.php

?
The site is here:http://www.scalemodellingnow.com

Any help please?!
Francis