Mercruiser Aluminum 496 manifolds with out water rail worth $450?
05-12-2016, 04:07 AM
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Mercruiser Aluminum 496 manifolds with out water rail worth $450?
Hey guys I need some help here. I found a set of Mercruiser 496 aluminum manifolds without water rail and risers for like $450. They have been in fresh water in Missouri for 150 hours look like they are in really good condition. But I have a buddy who has a 496ho and had the aluminum manifolds and he pressure tested his and everything and it passed, then once they heated up I guess there was a crack and hydro locked the motor. Now I will be running these in fresh water at all times. I just do t want to have to rebuild my motor again! I also found a set of emi thunders with sort riser so I can still use my stock "s" pipe with 50 hours on them for $1100 with shipping. So Mercruiser with 150 hrs or emi with 50hours? Oh yeah the emi were fresh water to. Thanks guys
05-12-2016, 05:07 AM
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Just my quick experience with those manifolds: My original 496 had the aluminum exhaust and they are very light and the ports are huge. I put CMI big tube headers on it and saw ZERO improvement. $4,000 for nothing. I think the price is a little high but for fresh water they seem to be very nice manifolds.
05-12-2016, 05:32 AM
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My 496 aluminum manifolds are 14 years old with 400+ hours on them. They still look brand new inside from what I can see. I was able to get a set of brand new aluminum manifolds to install when these go. Hopefully that will be many years from now.
Make sure you water pump is in good working order so they don't over heat.
Make sure you water pump is in good working order so they don't over heat.
05-12-2016, 09:05 AM
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I guess you made a good point with your thread. The manifolds passed leak test when cold but obviously didn't when heated up. Something to think about as even aluminum expands when heated. Make it a point to put in your oven when the ol lady is gone and then perform leak test.
Btw. 496 manifolds are great in my mind with anything up to 550 plus hp.
Btw. 496 manifolds are great in my mind with anything up to 550 plus hp.
05-12-2016, 10:40 AM
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05-12-2016, 01:35 PM
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The guy who is selling them said he heard from a mechanic that's fixing a 496 that the manifolds won't fit on the 454. The bolt pattern is different by 1 bolt. Is that true? I thought they bolted right up.
