The importance of measuring bell housing runout.

My 70 340 4 speed Duster was the first race car I ever built. Back in the 80's. The Lakewood Blow Proof Bell Housing was not aligning with the trans but I eventually got them mated. It made some squealing noises and could not be speed shifted AT ALL. Dick Landy recommended exteding the clutch arm a 1/2 inch but did not help. Most folks blamed it on the pilot bushing in the back of the crank, since I had never even looked for it out of ignorance. This article answers question's I 've had about that for 40 years. THANK YOU ALL!