Act 228 of 2004, which becomes effective on January 30, 2005, has changed certain equipment requirements for vehicles registered as street rods. The new language states that: “Vehicles registered as street rods will not be required to be equipped with bumpers, fenders or engine coverage as originally manufactured. If the hood, top and sides, or both, are removed from the vehicle the engine fan must be enclosed with a shroud designed to protect the fan from accidental contact from the outside.” As a result of this change, street rods will no longer be rejected for inspection for not having bumpers, fenders or an engine enclosure provided a fan shroud is present as required. These changes only apply to registered street rods. The existing rejection criteria found in Subchapter K (pertaining to bumpers, fenders and engine covers) still applies to specially constructed and reconstructed vehicles.

Source: 
Pennsylvania Driver and Vehicle Services - Safety Bulletin BI05-1 - January 2005

http://www.dmv.state.pa.us/inspections/safety_bulletins.shtml