Hard to explain maybe. My goal is to make as much power as I can retaining the factory A/C. The 67mm precision turbo is rated at 926hp. even though I know that it will not make that much in a Syclone but it should make 7-750? which is getting close to the limits of the stock block. Knowing that I will end up with 15k ish in the motor (steel crank is $3400 alone) I'm figuring a good block would be "cheap" insurance. Also give me some room to grow in the future if I decide to get crazy(r). I appreciate the advise, this is proving to be tougher than I thought but it's too late to turn back now!