Sneaky Wiring Question

[68steppsidee]

I am trying to possibly run my wires threw the edge of the inside firewall instead of having the block head mounted to it. Like possibly threw were the vent is and cut a hole and hide it behind the fender.. is that a good idea and anyone done anything like this... Will it be long enough to connect to everything still... Im running the starter wires inside behind the dash with a small hole to hit the starter