Vince, I have a brand new 4.125 sleeved LS6 block, JE custom pistons and Lunati 4.00" crank to make 427 all for $4600, I am saving up for a C5R block. Or I may just see how many stock blocks I can break, so far none. I would not go for the iron block, your too heavy already. You could have Brandon finish a set of our new Judson 6.0 heads and have something awesome. Good luck.