Just turn the 13mm pump down.
Here is one of my billet roller cams. I do it a little different for maximum strength and rod clearance.
That is just to show there are many ways of doing the same thing that can all work well. I know none of mine have ever failed and are in some of the top pullers in the midwest.
Ok guys this thread wasn't started so it could be hi-jacked into a "Cam Wars" thread. As much as Fireman450 would love to go to a billet cam, he is too pressed for time and money right now to have the block machined for cam bushings and have a billet cam made. He is just trying to find out if he can run a regrind with the 13mm or should he just sell the 13mm and have his stock 160 pump sent off and modified.