I want to gear down my F5 for a drag race but am not sure what gears to run. I wanted to change my bottom gear to a 42 or 43 tooth but I'm not sure it will fit with the stock 70 pitch chain. I don't really want to buy a larger chain. Does anyone know if this would fit? I was also thinking of putting a 19 tooth top gear instead but I was thinking that it would be too small. If anyone can help me out I would appreciate it. I am looking to gear it below 100.