because they crack right down the center of the block under the IM, when you make a lot of power. i mean over 5-600hp. i have seen to many on theturboforums that crack all the way down the middle of the block.
i am very happy with my choice on the block. there are better motors out there for sure. but for a budget build i will be happy with this motor and 800whp will be more than enough and the cast iron block will easily hold that.
Turbo Turtle Garage
Zetec and Duratec Turbo kits, engine building