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Thread: 64 Rivi / Headers or stock exhaust manifold

  1. #1
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    64 Rivi / Headers or stock exhaust manifold

    I have finally started taking out the 425 in my 64 Rivi for a rebuild. My initial goal is to keep it fairly stock with maybe an RV cam. She is all original so I don't plan to go too radical. Plus the wife and I plan on taking it for road trips.

    I guess the million dollar question is; are headers worth the hassle and extra cost over the stock exhaust manifold for stock applications? The more I read about this, the more controversy I find. I have always loved the sound but understand they create a lot of heat. Is there a great benefit over the design of the original exhaust manifold?

    Thanks -Jeff

  2. #2
    Jeff,

    Good question. I had the same question when I rebuilt mine. I had my engine on the dyno and did the comparison testing between the Sanderson headers and the stock manifolds. For my build the Sanderson headers are worth roughly (peak) 5 HP on my engine (with a moderate build), and up to 5 (estimate) ft-lbs of torque. The most interesting effect was how it changed the peak RPM. Because of how the dyno servo works, the pulls were done from 3000 RPM (hense the "estimated" peak torque).

    With the stock manifolds the torqe was already on its way down at 3000 RPM and the peak HP was at 4800RPM

    With the headers my peak torque was at 3600RPM and peak horsepower at 4700RPM

    There are better flowing headers on the market than Sandersons. TA Perfomance or even better is "Get Bent" exhaust has a very nice mandrel bent ones available. I have even seen them with 2" pipes with 3" collectors!

    As for the heat issue, I would recommend ceramic coating such as Jet Hot, or go a little cheaper and do header wrap and stainless steel wire, then use the high temp Thermo Tec spray coating to finnish them off.

    Erik
    Last edited by ahhh65riv; 10-29-2009 at 10:41 AM.
    _________________
    ROA 11755
    65 Riviera GS
    Black/Black (restore in process)
    See dyno break-in run here: http://www.youtube.com/watch?v=xuIKyzct4Sc
    See first dyno pull after overhaul here: http://www.youtube.com/watch?v=TWGYfCwEvO8

    86 LX Police Interceptor (SS) 5.0 Mustang
    (wifes drag car)

  3. #3
    As far as I'm concerned for a stocker type application headers are just to much of a HASSLE!!!! Stock manifolds really flow pretty decently for something stock. You can further improve things by doing some clean-up grinding which will help. My "Rockers" are less of a hassle & improve things MUCH more than 5HP. With them, since you are increasing volumetric efficiency your MPG will be better. It's all about being able to flow AIR!!!!!
    Just my nickels worth.
    Tom Telesco
    Classic and Muscle Automotive
    12 Cook St.
    Norwalk, CT 06853-1601
    Day Phone 203-324-6045 ET
    NailHead Mini-Starters '53-'66
    Adjustable Roller Tip Rocker Arms - All NailHeads
    Custom forged pistons
    Front & rear neoprene seals
    Many other "Nail" parts
    "If I can't get it, you don't need it!"

  4. #4
    Toms right! I would put his rockers on the top of the list far above the NEED for headers. I tested them too!

    I would definately port match the manifolds at the minimum. Tom has some ideas I almost persued about doing some modifications to the stock manifolds that may work better than headers could do.

    There is also contoversy weather manifold gaskets are necissary. What is your opinion on that Tom?
    _________________
    ROA 11755
    65 Riviera GS
    Black/Black (restore in process)
    See dyno break-in run here: http://www.youtube.com/watch?v=xuIKyzct4Sc
    See first dyno pull after overhaul here: http://www.youtube.com/watch?v=TWGYfCwEvO8

    86 LX Police Interceptor (SS) 5.0 Mustang
    (wifes drag car)

  5. #5
    We are talking about exhaust manifolds. NO, gaskets are not nec. But the manifolds & head mating surfaces need to be CLEAN!!!! They came from the factory with no gaskets from '53-'66. Heat is dissipated through the manifolds without gaskets.
    Tom Telesco
    Classic and Muscle Automotive
    12 Cook St.
    Norwalk, CT 06853-1601
    Day Phone 203-324-6045 ET
    NailHead Mini-Starters '53-'66
    Adjustable Roller Tip Rocker Arms - All NailHeads
    Custom forged pistons
    Front & rear neoprene seals
    Many other "Nail" parts
    "If I can't get it, you don't need it!"

  6. #6
    Join Date
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    Thank you both for your input. I will have the engine out so it will be easy to clean the surfaces. How much will I have to take off the exhaust manifold? Is this something I can do with a dremel or is it best left to a machine shop? Can you recommend any other manifold mods?

    Thanks again
    -Jeff

  7. #7
    Port matching is basically grinding away any "lip" or "overhang" into the flow of exhaust by "matching" up the port openings. No need for a machinist as a dremmel will work fine for all you will be doing. It's not really even necissary, except for squeezing out every bit you can of "free" horsepower, other than your time and elbow grease.

    A manifold sits a lot closer to the head unlike a header that has to have a minimum pipe outward before the first bend. When you get your manifolds off, look inside the port. On mine I could easily see the carbon trails inticating the natural flow path the exhaust flow is trying to take as it comes out of the head. It would be experimental, but basically you would try and straighten the flow into the collector of the manifold. There's not much meat there to grind away, and this is just me thinking and wondering... I cant profess to this but it has been claimed to get a hp increase just by raising the manifolds up as high as the bolt holes will let you before tightening them down.

    Erik
    _________________
    ROA 11755
    65 Riviera GS
    Black/Black (restore in process)
    See dyno break-in run here: http://www.youtube.com/watch?v=xuIKyzct4Sc
    See first dyno pull after overhaul here: http://www.youtube.com/watch?v=TWGYfCwEvO8

    86 LX Police Interceptor (SS) 5.0 Mustang
    (wifes drag car)

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