You can, but that makes no sense.. Why? Efficiency, money, time, amount of work. And in fact, if you ask 'Can I', it make much less sense in any attempts. No offense, but getting professional to suit your fireplace to work on gas or cooperate gas and wood (ashes in nozzles.. Yuck) will be !such more expensive than gettinfg professional installation with gas fireplace cost.

And in case of anything.. I know it's DIY subreddit, but some things are just too dangerous to mess around with them without enough knowledge..