To start a customised private bitcoin core blockchain, all i need to do is:
1) change the genesis block
2) change the timestamp of genesis block
is there anything else?
what do you mean by private bitcoin core chain?
1) bitcoin core it's just a client, so use bitcoin blockchain term.
2) do you want to fork bitcoin codebase? In this case you have to change more parameters than genesis block: port number, magic message number ect.
3) But if you just want to run private bitcoin blockchain for your own testing or something similar, you don't have to change anything
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
just start daemon with -regtest option.