Did you replace the pilot bushing?
From Rockauto.com:
DORMAN Part # 690034 More Info {#14651, 6900341} Inside Dia: 0.593"; Outside Dia.: 1.060"; Length: .751"
Only Used For Auto Trans Conversion; Powerglide to Manual Trans; O.D. 1.060"
Only Used For Automatic Transmission Conversion; Powerglide to Manual Transmission; O.D. 1.060"