1990 la roller 360........cam question

I can't say with 100% certainty on this one, but .550" at the valve assuming a 1.5:1 rocker would translate to a .367" lobe lift, and I can't see that as being an issue with the stock type lifters unless the ones you have are shot or if you don't have enough spring to hold them on the lobe.

Can you up the rocker ratio to net your extra lift?