Time to build the motor

I am now leaning towards the same kit. I read on some earlier posts that with the H beam rods you do not have to clearance the block as much. Also, when they refer to clearancing the block is it as simple as taking a die grinder with a carbide bit and "trimming" out material until the corner of the connecting rod clears the block as you spin the crank? How much clearance do you need?