Dustflyer,
Here's a little more speed tip for your current Whiplash with the Jett 60L...
Instead of using a 10x8 prop, go with the APC D-1 hub 9.5X8.5N (part # LP09585) racing prop, which should give you even more speed with almost the same amount of thrust without having to retune the engine/pipe combo. Although, you can fine tune it even further to get more rpm from the 60L. This prop will definately give you both the speed and thrust that you're looking for.
Here's a link to the prop mentioned...
http://www.apcprop.com/store/agora.c...1145&ppinc=apc
Hope this help!