The arm should only go on one 1 way. The shaft should have 3 flat sides and 1 rounded side. Also make sure that its the correct motor for an a-body check that it has 4 silver terminals, if it only has 3 it won't work for you. Use this test to make sure it works correctly and to park the motor. Any other questions post here, PM me or email somerbr1@aol.com

My website ns1aar.com

Thanks
Bruce