I am running 1.65/1.55 Jesel rockers and if I remember correctly ( I will look in the box with the old pushrods and lifters) it was a mixture of centered and off centered lifters. From a geometry stand point I think all of them were straight, the offset corrected that. If you notice the hole on your stage heads, it may have been widened oblong to account for the shift. I will try to get some pics tomorrow to verify.