Be careful of those roller cams- most are Magnum cores, which will do two things in the OP's case:
1.) They are short-nosed cams that will lose you the ability to run a mechanical fuel pump, unless you use the Hughes cam adapter.
2.) The cam specs will be off when used in a roller LA, since the Magnum uses a 1.6:1 rocker ratio and the LA uses 1.5:1 .