BOTH OF THE MANIFOLDS IN THE PICTURE BELOW ARE STOCK HONDA ACCORD MANIFOLDS. F22A1 MANIFOLD IS ON THE LEFT, F22A4 MANIFOLD IS ON THE RIGHT. F22A4 MANIFOLD MAKES ABOUT 5 HP MORE THAN THE F22A1 MANIFOLD AND IS 1/3 rd THE WEIGHT. F22A1 IS A CAST UNIT WHERE THE F22A4 IS A TUBE DESIGN. TO MAKE THE F22A4 MANIFOLD PERFORM BETTER REMOVE ENOUGHT WELD FROM MANIFOLD TO ALLOW BETTER FLOW FROM BLOCK TO MANIFOLD AND SAME WITH EXIT OF MANIFOLD AND ENTRANCE OF DOWN TUBE AND SWIRL POLISH THE TUBES, THIS REMOVES WELD SPLATTOR AND BUILD UP DEPOSITS, WELDED AREA IS SHOWN WITH YELLOW CIRCLES, REMOVE JUST ENOUGHT WELD TO HELP FLOW,I YOU REMOVE TO MUCH YOU WILL HAVE TO BRAZE THE FRONT TUBES OF THE MANIFOLD.ARC/MIG PUTS TO MUCH HEAT INTO THE MANIFOLD AND CHANCES OF WARPAGE IS GREATER. YOU ALSO WILL HAVE TO MATCH THE GASKETS AFTER METAL REMOVAL FROM MANIFOLD

THE F22A4 IS A TUBE DESIGN WERE THE TUBES ARE PRESSED INTO THE FLANGES AND WELDED 360 AROUND THE INSIDE OF THE FLANGE TO TUBE. LET IT BREATH

MY NEW EXHAUST WILL HAVE A 2.50" TO A 2.25" REDUCER TO 2.25" TUBING TO THE CHERRY BOMB TO A 45 DEG ELBOW TO 1.5' OF EXIT TUBING OUT THE SIDE...THE OLD EXHAUST WHEN IDLING WAS ABOUT 225 DECIBLES.