I have an opportunity to pick up a stock set of heads for the 8.1 at a bargin price. I am thinking about picking them up, and then having them ported and polished etc.

Has anyone else tried this? Worth it or not on the 8.1?

IMO,its only worth it if you use other airflow mods like headers,exhaust,and a camshaft/intake work to make the extra airflow useable. The reason most ppl just go with forced induction is because it allows you to use the stock internal parts,and force more air thru the engine with just an exhaust,and without a major engine teardown.The power gain is about the same,but forced induction usually gives stronger bottom end torque,but requires higher octane fuel.