How do they compare to the Vortec heads? Would it be better to get Vortec heads or a good port & polish jobs on the heads of an L98? What are the valve sizes of an L98 also? I was looking at maybe picking up an L98 and building it up for performance and one of the first things I'd want done is the heads and cam.

 

L98 heads are decent, but the efficiency characteristics, flow #'s and raised runners all add to a superior head over the L98's.

I would go with the Vortecs, but that's just MO. If you want more power go Vortec.