It all depends on the budget of course but if the money is available I'd buy aluminum heads for that engine. The modern chamber design in the aluminum heads will allow you to run pump gas and you'll lose a bunch of weight off the nose of the car.
You should be able to sell those Stage IV heads for a decent amount which will offset some of the cost of the aluminum heads.
Well the budget is that of a 16yo and 13yo whose income comes from mowing the lawn so different heads are probably not high on the list. This is primarily a learning experience for them.
That brings up another question though. The last pair of heads (906 heads)I sent to the machine shop came back with cracks in the valve guide towers. They claimed that was normal and not a problem. Another machine shop told me the same thing. I don't agree. I think this would cause oil to be sucked through into the valve guide. These are experienced shops that build a lot of engines. Is it unreasonable to expect my heads to come back with no cracks?
