H/C/I what else to replace??
Replace the timing chain while you're in there also
Are you set on 241 heads? What heads are on there now? If you're looking for big power gains, stock 241 heads will not be your answer.
if you want cheap power go get some 5.3 truck heads (862s) out of a junk yard somewhere and have your ls1 valves put in them with some new valve stem seals. youll get more compression without sacrificing ptv clearance and theyll flow exactly the same as any ls1 head.

