Roller cam/lifter problem

I thought hughes roller lifters were made just for this specific problem?

From their website
Made in U.S.A. by true craftsmen.
These are oil thru lifters and will oil through the pushrods if you need them to.
The oil band has been lowered so that the small blocks with the chamfered lifter bores no longer have to be sleeved.

* The lifter bores do not need to be bushed to run these lifters.
* DO NOT use these lifters with a flat tappet cam!