Abstract: A guide device for use with a pulley block of the type utilized by utility lineman during installation of an electrical power line is disclosed. The guide device is a generally C-shaped member having inwardly converging curved leg members projecting from a body portion thereof. The guide device is permanently captured within the pulley block in its functional position wherein the C-shaped body member engages the pulley wheel to prevent a lightweight feeder line extending through the pulley block from slipping off the pulley wheel and becoming jammed in the installation process. Thus, the present guide device eliminates the need for repeated climbing of the power pole by the lineman during the process of feeding the power line through the pulley block thereby providing obvious economic advantages.