496 manifolds on a 502 ?
 

Slow in here due to the cold-a$$ weather !! Here's one for ya':

I've read, on numerous websites, that stock Merc 496 manifolds will bolt perfectly onto a 502 with zero modification. First of all, is this true ? Secondly, would there be any benefit ? I'm having a hard time believing that it will work simply because I've never read it on either TBM or OSO as being a desirable option for us 502 owners. If nothing else, the 496 manifolds appear lighter than the stock 502 jobbies. Just curious...

Rock

They fit. Why you would want to replace a stock piece for a stock piece is beyond me. Get some Danas if you want a good manifold for a reasonable price.

5 good reasons
 

1. Dry joint
2. Much better flow
3. Alum. 496 manifolds weigh nothing compared to a heavy 502 cast manifold.
4. they look cooler
5. they don't cost $2500

If I were going to spend the money it would be for a performance manifold that can be bought for roughly the same price as a stock piece. Plus they come polished or anodized at no additional cost.
Buy what you like. There are some good pieces out there, stock & aftermarket. The Merc pieces are just fine & if you can find a used set of 496 manifolds for little money, buy them. BUT if your stock pieces are not broke, don't fix them.

You really can't beat the price of a 496 take off manifold/riser. I have seen them for as low as $200-300 a set. Thats cheaper than a cast set of aftermarket osco manifolds.

I am going this route when it comes time to replace my exhaust on my 330hp 454s... I got to have somthing let over for gas money.

So They fit then???

I need a set for a 330 also.

They will breathe better, but not drastically better.. However they are lighter (assuming you get the ones that are the aluminum lowers & not cast iron manifolds) & you would have the dry joint exhaust as well as a stainless riser.. For a stock 454/502 on a budget thats a good way to go if you get em right.. Otherwise you might as well Go SM, Gil, Dana or CMI... :) Jamie / Lakeside


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This is now a parallel thread on TBM but that's neither here nor there. What about the shift/ECM brackets and closed cooling ? Anybody know where to get a flow diagram for the 496 motor so it can be replicated with or without closed cooling ?

Oh yeah, one more thing. To all the "buy Dana's, SM's, RMI's, CMI's, etc. etc" people ...this question pertains to all the people who boat in salt water and HAVE to replace their manifolds & risers every so often and want to stay stock, not to someone looking to gain a little HP for a lot of $$$. If I had $2K burning a hole in my pocket, this would be a different thread...but for $500 or less there is no other alternative. The simple fact that they're cheaper and lighter than the stock 502 parts makes it worth looking into and, since it was 12 degrees out yesterday morning...what the hell else are we going to talk about ? :cool-smiley-027:

Rock

Water enters from the bottom & exits on the top. As far as ecm, shift & oil brackets for adapting 496 to 454-502 you wil need to be creative.. :) Jamie / Lakeside

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