Change Apache2 80 port to 8080 (Impossible..)

Hi guys!

I want to install varnish cache program on centos 6 , because i have many memory but.. the sites are not fast enought :)

My problem is to install this program , i have to change the default 80 port to 8080

But if i change the 80 port the apache not will work anymore...

Checked the firewall add port 8080 delete 80 , and etc. But always the system create the http service port : 80.

So the apache2 work on port 80... Just on THAT.

How could i solve this?