How much are the off set rockers?
From what it sounds like the pro comps require it while the Edelbrock one allow you to use you the rockers you already have. Just Sayin.
Hughes rockers are about 700, so basically the difference in price between the RPMs and ProComps. The thing is the ProComps are apparently a copy of the Edelbrock Victor head (hence the need for off-set rockers but, they only flow like the RPMs.