[EricStaab]

In some cases we can get better or the same, and some the flat is faster. The roller really shines when it comes to durability and increased spring pressure. With out having flat tappet lifters made from exotic materials, and coatings it is hard to get them to be as durable. The spring pressure is a very important part of making horse power. Having too much, it will take more hp to turn the cam. Having too little will cause all kinds of problems such as valve float, valve chatter, wearing seats out faster, loss of cam timing, and more. Sometimes you can make more power with the flat tappet. Sometimes you make more with a roller. It can really depend on the application. On the durability side I give it to the roller 90% of the time.