572 Hemi / Is it Worth it?

I have a problem. I have a 69 dart that I am toying with putting a 572 hemi out of. I just started ordering some of the parts to put the motor together. The problem is that I am getting cold feet and was curious if I should keep pursuing the hemi install or should switch back to a RB motor for simplicity. The block I am starting with is a world block, is that any different than the 426 hemi block?

I was just curious if there is someone that could give me some direction and tell me if it is worth the headache of the hemi. It looks like a lot of work and alot of fabrication. Is an aftermarket K frame worth it. Thanks for the help.