School me on W2 heads.

I would like to know this as well. Are they all iron, did they make aluminum w2 or were w5 and w9 heads the aluminum ones? Long valve, short valve, pedastels or none. Valve sizes, I've looked for a descriptive writeup of these just like the op and haven't found a good one. I'm not a small block guy but from what I've seen and read the w2 make awesome power even compared to today's heads. RRR or yellow rose, rumblefish, krazy and cracked,I know u guys can spit some info on these.