We have not been modifying stock VW cases to accept the much larger Chevy hydraulic lifters, as some companies do, because of the extremely high failure rate. To do so makes the original stock case so thin the strength is reduced radically and breakage of the case at the cam follower boss is almost assured, especially with any higher performance (other than stock) camshaft. Some people have gotten away with this combination by using extremely mild ramp angle cams, high ratio rocker arm camshafts, however, the only proper way I have found to do this is with a lifter that fits the hole in the first place, unfortunately these lifters have not worked well.
With the new cases that are made to go to Mexico this boss area has been increased in size to accommodate the VW factory hydraulic lifter that is similar to a Chevy. |