I am wondering if anyone here has tried to add an external oil feed to a 06 to 09 yz450f head. I am starting to get parts to build up a new 426 bottom end with 66.1mm stroker crank and a JSR 98mm tall deck cylinder for a YZ/YFZ450. I planned on using a 05 YZ450F head but I am having a hard time finding a good low hour core to use. I have been looking at the some 06 - 09 and there are a lot more available, are they much better then the 03 - 05? I am going to have the head ported and run +1mm stainless steel ferrea valves and springs and have the buckets WPC treated not sure on what cams though, will probably try a few.