Speaking of aluminum heads...My performance machining professor just got a sweet deal on some heads for his 460 drag engine, he payed $2700 a piece for the heads when they were I think $3400. Anywho, he was going to deck them like .002" because he didn't like the finish on them, and while they were on the machine, as it was sweeping across, it got caught on the end of the head and shoved it up, and took about a 1/4" gouge out...he got so pissed the he threw them on the ground. Turns out, he could have had them welded up, but now that he threw the one, it probably cracked like crazy...Sorry it was really off topic...