Cast or Alum.heads for racing.
Hey Scott, Just my measley 2 cents Canadian; We ran X heads back in the day. I had a set on my 340 that were ported by John Rossiter racing with big valves. My buddy ran them on his hairy solid lifter motor (hairy for the 1980s)They flowed great..........could never afford W2s with all of the add ons. The X heads worked great. Don't know much about aluminum heads but I know less weight = low ET.:cheers: