l ENGINE INSTALLATION INSTRUCTIONS A PART N0 3998333 CONT G GENERAL INFORMATION CONT I g I 8 The intake manifold of this engine is equipped with a vacuum source located on the center branch gfor the crankcase ventilation system lf desired thisvacuum source canbe used on past models by re 3 moving the dust seal and installing connector part number 3859374 transferring the hose and clamp from the outboard fitting to the connector A IMPORTANT If the above source of vacuum is not used plug the opening with a 3 8 cup plug Part N0 838323 3 lf converting to use the added sourc e of vacuum plug previously used opening with pipe plug Part No 445673 I R lf above is used on vehicles equipped with vacuum power brakes seal previously used source of ventilator vacuum by pinching tube to prevent leakage GM PARTS DIVISION GENERAL MOTORS CORPORATION CHEVROLET 72TL l 50 I A e