I am going to replace my water pump with a hi-flow water pump. I also want to replace the timing chain. I have did a search with not much help. I wanted to know is there any advantage to a double roller or should I just get the standard? Does it come with the gears or should I get those new too? Advance Auto has an Edlerbrock for $33. Any help is greatly appreciated. I have a 89 5.0l no mods as of yet.