{
"nonce": "0x0000000000000042",
"difficulty": "0x000000100",
"alloc": {
},
"mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"coinbase": "0x0000000000000000000000000000000000000000",
"timestamp": "0x00",
"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"gasLimit": "0x16388"
}
This is a blank genesis block.. you can make changes to this and make it how you want.. Also, you can go to
https://gist.github.com/frozeman/83c90a0b451b86f679ba and make modifications as required by you..
I would suggest you to set a higher number for gas limit and low difficulty level..