[CentOS] Query regarding grub.conf in centos 6.5 iso

Hello Greetings,

I am trying to customize centos 6.5 iso and have few questions.

I can't get the significance of grub.conf inside the isolinux folder. I
thought it would be used by anaconda to generate /etc/grub.conf. But it
seems that is not the case. I tried to make some changes to it, which
haven't had  any effect in /etc/grub.conf.
So, may I ask what is the usage of that grub.conf in the iso? And how can I
alter the /etc/grub.conf that is getting generated by anaconda ( I don't
want to manually edit it, but I want to add some extra configurations to it
as part of installation)

Kindly correct me if I have misunderstood anything.

Thanks & Regards,
Aravind