Give the boyz at BEST Machine in Michigan a shout if you wanna find the gremlins and angels in the aluminum alloy blocks. They seem to have it all locked down and are machining a host of Indy blocks to perfection.
That being said, myself compared to anyone here on the issue of weight, I am still running an iron factory block. But then again, I'm not making as much steam as some of you guys are.
Maybe an aluminum block is in the future unless I trim enough weight off the car all together to not need the special alloy block.