I'm thinking of removing a section of the 5" cinder block around the red brick next one of 2 chutes in the 30' chimney of my house. Then i will drill/cut/chisel out a 4-5" hole from the red brick and insert a pellet vent, connecting it to a liner going to the chute top. Will the chimney fall over? How much will the removal of some cinder block and brick comprimise the structural integrity? Am i doing something terribly stupid here? Thanks.