The springs suggested severely lack in seat and open pressure and will ultimately send you to valve float prematurely. There just simply isn't enough pressure exerted to maintain control ability in the area. This is the reason why I use the JWT HD springs in place of the ones suggested. The only other springs I would suggest would be the supertech dual coil springs offered for the VG.
The suggested springs for this particular lobe profile are good for 8000 RPM. This was tested by the engineer that designed the cams. While the JWT springs you suggest will probably work fine, they are overkill in most cases.
