FORM 1361 (REV. B) 02/03 INSTALLATION INSTRUCTIONS ENGINE MODIFICATIONS FOR O-RING DISTRIBUTORS GENERAL INFORMATION Some distributors for Chevrolet engines have two o-ring grooves on the lower shank. These distributors require the engine block’s distributor hole and oil gallery holes chamfered approximately 0.060” x 30°. This is to remove the sharp (cutting) edges of the distributor hole and oil gallery holes. DO NOT USE O-RINGS IF THE ENGINE IS NOT MODIFIED. The o-rings will be damaged during the installation of the distributor and debris from the o-rings will fall into the crankcase or lodge in the oil gallery. If the engine is not modified install the distributor without o-rings. ENGINE BLOCK DISTRIBUTOR INTAKE MANIFOLD INTAKE MANIFOLD DISTRIBUTOR HOLE ENGINE BLOCK CHAMFER, 3 PLACES APPROX. 0.060" X OIL GALLEY OIL GALLEY OIL GALLEY OIL GALLEY NITRILE O-RINGS, 2 PLACES ID: 1.114 ± 0.010 THICKNESS: 0.070 ± 0.003 MALLORY IS A DIVISION OF THE MR. GASKET PERFORMANCE GROUP 10601 MEMPHIS AVE. #12, CLEVELAND, OH 44144 216.688.8300 FAX 216.688.8306 www.mrgasket.com FORM 1361 (REV. B) 02/03 Made in U.S.A. Printed in U.S.A. 1