Yes I was and still am thinking about swithing the 03 cast iron blockout for the aluminum, but still undecided. And in regards to the reliability of the aluminum I've heard it is good for 1000 hp and that ford did switch to the cast iron because of costs but heres my thoughts on that. Cast iron is going for $7 per 100 pounds and aluminum is going for around $60 per 100 pounds but the block before machining cant weigh more than 300 pounds so your only talking about $160 difference but with the aluminum there is alot more costs in machining because the aluminum has sleeves in it which could cost a few hundred more, therefore the total savings could be around $600 per motor make you wonder??? On the other hand I did read somthing about ford testing the supercharged cobra with an aluminum block and they kept cracking. Still not sure what I'm doing with it but if I do make the swap I'll posts some details.