I'm already spraying approximately 30% of peak power. When I hit it around 3250rpm I'm probably close to 50% don't really want to hit it much harder than that. I have jets to go to 125hp and higher. But I want to upgrade heads to for more power regardless. I think it would be a fun upgrade to do and would like advice and knowledge on the subject of upgrading j heads to aluminum woth my combo. The faster the better in the end and if the aluminum heads get me more power across the board and also prevent detonation then I can safely up the nitrous too.