Another question I have been thinking about is aluminum w/out NOS or cast iron vortec w/NOS. I have been told that aluminum heads can't handle NOS, and am not sure on the validity of the claim. I love the low end torque that my little 305 has right now, so I'm tempted to set up the edelbrock with vortec heads and add a 100 shot of NOS to play around with. I don't have the money for any of this right now so all I'm doing is just talking and thinking about it. I have found a set of SBC alumimun heads on e-bay that are fully assembled and shipped to your door for around $650. The only worry I have is that they might be a cheap head and end up being worse then if I got some cast iron heads. What do you think about that?