That I am aware none of the truck motors came with a stock roller rocker/cam setup until the L31 Vortec 5.7 motors, I think around 1995 or so. I believe what happens is a lot of guys see the center bolt valve covers on the junk TBI motors and confuse it with a Vortec roller block. Wishful thinking as it may be pretty much any truck motor that had those TBI heads was never a roller rocker until someone put a roller rocker in it, and unfortunately if they put those old "swirl port" heads back on then it was a waste of money and a roller rocker, aside from the extended wear of the cam and lifters (which would be like more of a curse than a gift). I may be mistaken but I think those heads were such junk that they never even made an intake to throw them on a roller motor with the Vortec 5.7 FI still intact.