I have tried this before to send emails with assignments appear they where sent earlier than i had sent them. The simple answer is its impossible. I have tried setting the message meta tags over php (can be used to problem a quick mail client) that i use, but every time i put the time/date meta tags, the message was picked up by spam filters and sent back failed. It may work if you where sending to a message filter without spam filter, but the changes are 1/100000000000+
Only thing I can suggest, Photoshop or if your using Google chrome, right click on the time, click on inspect element, change the value on the html to the time/date you want!
(Original post by CameronMurray)
It is for coursework, because I could not find a client, I had to just fake it and do the work!
Therefore now I need to makeup a load of emails.
I would then just photoshop it then. Its what I did when I had to go interview/questionnaire people and couldn't be bothered. Just send a email to your account from your fake account. Print screen it, but don't resize it and paste it on photoshop. Try and get a similar font and and write over where the original date is and have a white background so you can't see the original text.
As others have said it's fairly easy to do to be able to pass a trivial test (What's shown in the message summary).
To have something that could pass some scrutiny gets much harder. e.g. emails usually pass through a number of email servers all of which add in a header which includes the date and time it got to them.