496 Exhaust manifold
11-22-2013, 05:23 PM
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496 Exhaust manifold
Can anyone tell me if there are any differences between 496 exhaust manifolds other than being cast iron or aluminum. I see them listed with water rail and without. Do all the 496 have water rails? I have a closed cooling system what would be involved in plumbing these manifolds on a 454 closed system? Thanks.
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11-23-2013, 02:53 AM
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There shouldn't be any problem plumbing them for closed cooling, the only real difference is the fitting on the bottom that feeds in from the elbow but instead of a drain screw they drain to a valve at the bottom of the engine. You should be able to replace the fitting with a normal elbow with the blue drain screw & be good to go. Randy
11-28-2013, 06:13 PM
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Has anyone done the change from the 454 to the 496 manifolds ? did you see any improvement from the stock 454 manifolds the biggest reason I want to use the 496 is to get the water away from the engine in the manifolds and risers. Not really looking for something to go fast she is a barge at 38ft and 15000 lbs. Jamie
11-29-2013, 02:02 PM
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I have kind of done it using using aluminum 496 manifolds on a 502..... Much better design than the older log style exhaust and I would think at least a 20HP increase even with a mild motor..... Plus the weight savings is huge. I can pull a manifold and riser off with one arm easily! I would assume you are going to use the cast iron manifolds as they discontinued the aluminum many years ago.... But still, the stainless risers weigh nothing compared to stock 454 style stuff..... I did have to get the 496 style remote oil filter but I was starting from scratch. You can probably re-locate yours pretty easily. The dry joint riser is far better than the old style and I would say anybody needing to replace the old style wet joint manifolds should use 496 style exhaust if you are not afraid of a little fabbing.......
12-01-2013, 12:10 AM
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My boat is a inboard so I wont have to fab anything for the oil filter it has a bracket that mounts on the bell housing of the velvet drive. The dry joint exhaust is what I really what I want more than the performance because my boat is big and heavy, but the weight saving also sounds good. Thanks to all that have replied it has given me some ideas, Does anyone know where I could locate a water flow diagram for a 496 HO ? I searched the net but haven't had much luck. Jamie
