I'm not trying to destroy your thread or to insult you. I'm just giving you a factual and real-world advice.
I sell about 40 pair of cylinder heads a month and I do port work on a daily basis. You definitely can run L-98 heads, just don't expect to easily achieve 500 ponies.
Anything can be accomplished, but at what price?
My advice is that it will be more cost effective per dollar to sell your L-98 heads and get something that is much more suited to your application.
You really need a minimum of 200 CC runner size. I saw some brand new Brodix aluminum heads on a close out at $600.00 per pair bare.
Now, those kinds of deals are out there if you shop around.
However, if you really want to use your existing heads, there is no doubt that you can, but again, I'm just being realistic about achieving 500 horsepower.