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  1. #1
    Petty Officer 1st Class Valv's Avatar
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    Default Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    I have a Mercruiser 188hp with a Ford 302 V8 and 2 barrels carb, is it worth to find a manifold and 4 barrels carb to upgrade HPs ?If so, how much of a gain can I expect ?Thanks.Val
    1992 Silverton 34 Convertible w. dual station
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  2. #2
    Lieutenant Commander flashback's Avatar
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    I,m not an expert on this but let me throw out a few ideas and see what happens. First, a lot would depend on what you use the boat for. The 4 barrel will get you out of the hole faster if you are pulling skiers which is generally a good thing, but if you run the boat at WOT all the time, your fuel consumtion will double, that,s not a good thing. Anything under about 2500-3000 RPM and the other 2 barrels on a 4 barrel are not working anyhow so nothing will change it is only when you get close to WOT that the 4 barrel is an advantage as far as power goes. all in all, you may see 15 or 20 more horsepower at top end..The cost, if you went with new parts would most likley be in the range of 800 to 1000 dollars. hope this helps in your decision....
    The Devil to pay, and no pitch hot!

  3. #3
    Petty Officer 2nd Class
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Wow, 800 to 100 dollars. What are the parts made from, hardtogetium? I did exactly what you are talking about on my 190HP OMC. I do enjoy the difference and being able to hear the secondarys open. I used a Weind Stealth Man. And a Holley 4160. My total investment is $250, and worth every penny. I can hear the sec. close at about 4200 RPM, at that point I am cruising on less gas than with the 2 bbl. GO FOR IT, www.ebay.com is a wonderful place...Al...

  4. #4
    Moderator Bob_VT's Avatar
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Well since we are in a money spending mood I would also suggest that if the carb and manifold is changed go with a better camshaft. The 302 is a very capable motor and depending on it's age depends on how far you want to push it. Boosting an older motor without a full rebuild could drastically shorten it's lifespan. The carb and cam combonation will certainly raise the hp. We all enjoy more power.Bob
    This is a great link to boat specifications http://boatspecs.iboats.com/
    Please, shop iboats first!!


  5. #5
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    what EXACTLY do you do on a rebuild?just pistons and rings? or could you list some specifics?thanks

  6. #6
    Senior Chief Petty Officer
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Hey Bob I agree with the 4bbl. upgrade but ive found changing to a auto cam can actually lose mph. these engines are made to run at4200-4600rpm. If you do a cam change you better do your homework. you may defeat the purpose.

  7. #7
    Petty Officer 1st Class Valv's Avatar
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Thanks guys, I just bought this older Century 24ft. with rebuilt motor and drive, I was just wondering if with few hundreds I could squeeze some extra power for better cruising, I am afraid 188hp will have to be almost wide open to obtain plane anddecent cruising speed, and gas mileage won't be good. I was actually thinking at a Holley carb myself.
    1992 Silverton 34 Convertible w. dual station
    1990 Baha Cruiser 260 Fisherman

  8. #8
    Moderator Bob_VT's Avatar
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    FYI Crane cam's have specific cams designed for marine use.Bob
    This is a great link to boat specifications http://boatspecs.iboats.com/
    Please, shop iboats first!!


  9. #9
    Lieutenant Commander flashback's Avatar
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    If You can find a NEW carb for less than 450.00 dollars, let me know......
    The Devil to pay, and no pitch hot!

  10. #10
    Seaman Apprentice
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    and switch to 351 heads..... they breath better>>>Bigger vales ....just make sure the Marine Manifold will line up.

  11. #11
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    The old 188 uses 351 heads and 351 cam. If you change to a 4 barrel, you'll need to find a marine 302 manifold, which is getting hard to do. Then find a marine holley to fit it. If you can do it for several hundred dollars, you'll be lucky. Then you'll have you a 233 Mercruiser. Being Mercruiser quit using this system in 77, your engine is at least 25 years old. I'd leave it alone and baby it or your next post will be under the "I need a engine" heading.

  12. #12
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Listen to capt ken...its not worth the bother to screw up a running package....dont listen to these guys about cheapo aluminum manifolds, they were meant to have antifreeze run through them, not raw water! they corrode away in short order, dropping water in the oil pan...mercs 4 barrel 302 was rated at 225 hp...and I always thought it was a little generous.

  13. #13
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Wow, thats a new one to me. You mean the cast iron 2 BBL Ford manifold I took off my boat was a "Marine" manifold. Looked exactly like the one on my old Mustang. I am astounded by the responses I see here. There is a marine holley on ebay at $50 right as I am writing this. Your motor still has a Blue Oval on it a 302 part will fit a 302. Don't be afraid...

  14. #14
    Senior Chief Petty Officer
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Article about marine carbs. Marine and auto carbs have major differences, both legally and operationally. Yes an auto style carb will work but not advisable.When you run a 4 barrel as opposed to a 2 barrel, you will normally get better mileage with the 4 at lower rpm as the primarys are smaller than the 2 barrel. The 2 barrel has to operate at all rpms. Not very effecient.Try a Holley Marine carb, 600 cfm, mechanical secondarys.As to the intake I would suggest an intake from a "Boss" 302. They breath a little better than most stock iron manifolds. Aftermarket intakes are mostly aluminum and will not hold up in salt.

  15. #15
    Seaman Apprentice
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    If you are running non-cooled Cast iron Manifolds......>>>>make sure you Insurance premium is Paid.....

  16. #16
    Petty Officer 2nd Class
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Do you have a picture of a non-cooled cast iron manifold, I would love to see what one looks like. In 18 years of working on Fords I don't think I have ever seen one...Al...

  17. #17
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Be careful of making sure that yours has the 351 heads. My 888 does not, but I don't believe it is original either. The engine is a marine 302 and has a Merc tag. As someone mentioned above, mine appears to have a regular Ford intake. Actually, most of the major internal parts are Ford stamped.

  18. #18
    Petty Officer 2nd Class
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Marine engines are great, don't get me wrong. The ford Windsor small block is still a ford Windsor small block. 260-289-302-351 all can share common parts like heads, the 351 heads take larger head bolts to put on a smaller motor. The Eshaust ports are bigger on 351 heads, but the intake side of the motor is virtually unchanged between them. No hate mail please, the 351 is 1 inch wider, yes... I know you are computer literate if you are reading this, so get online and get you a four barrel combo and get out on that lake and have some fun with it...

  19. #19
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Lots of good info here, something to consider though is how do you plan to use the boat. Comming out of the hole important? Is mileage important? I know that on my (2) 888's the rated WOT is 3800 rpm. Is your prop matched to your engine, or your desired performance?When you start playing around with extra hp remember that those engines are getting older and you may need to shore up the bottom end to handle the extra umph! Good Luck!

  20. #20
    Seaman Apprentice
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Sorry, I was refering to the"Exhuast Manifolds".....Must be a Local Language thing..... the "Intake" is what we nail the 4 barrell too.....

  21. #21
    Petty Officer 2nd Class
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Wally:Oh, that makes much more sense now. Al...

  22. #22
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Valv,Speaking from similar experience, do it! It's totaly worth it. I have a 305 gmc OMC that was rated @ 185 hp. Here is what i did;1. New Edelbrock Marine Carb #1409 (COST $260)2. New 2101 intake (Cost $109)3. K&N marine spark arrestor (cost $75)4. 1.6 ratio roller rockers (cost $75)5. New exhaust manifolds (cost $350 Old ones where leaking!6. Other basic tune up parts and tricks (timing etc...)Total cost was under $900 (under $600 without the exhaust manifolds) yielded the following results;1. WOT speed of 43 to 53 mph - GPS not speedo.2. WOT rpm went from 4300 to 5300 All this forced a prop change! stainless (cost about $350) I am still working on finding the right prop for this setup though...

  23. #23
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    The first engine I rebuilt was a 302 for a 69 mustang car. With stock manifold and 600CFM holley 4bbl carb the difference was from 190 HP to about 220. I just sold a 67 CorrectCraft Mustang with a 289 (302 with slightly shorter stroke) It had a stock 2 bbl at 190hp. Correct Craft rated the 4 bbl at 210. If you can find the Marine carb and manifold cheap it may be worth it. For new parts is 20 to 30hp worth $600. You can probably get away with the same prop. Note, if you start looking at new cam, 351 heads (they are semi hemi and were used on the ford BOSS 302) you are now looking in the range of 290HP with a lot more stress on the engine. This is close to 1HP/cu/in. Not many engines achieve that. The BOSS 302 used 4 bolt main bearings instead of the stock 2 bolt mains. As others mentioned with all that additional HP you will be turning your prop to fast and will need to find a new prop. A prop shop can help calculate what you will need but that will add another 300 to $400. And add the new heads, and cam so that the big valves in the 351 heads can breath, and now you're in the 1200 to $1500 range. It is a lot of work unless you really need it. My suggestion for is go for a Mallory marine elctronic ignition. It will give your great starts and consistent running all year long.

  24. #24
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Or you could go the easy route use the 4 bbl and Weiand stealth, change to a set of 1.7 roller rockers. You'll get more lift from your cam and never have to pull the front cover. I've seen the stealth work well on mild engines and serious engines too. A great all around intake. I dont know the answer on the corrosion from fresh water with aluminum intakes, but I have no reason to doubt it- just ignorance, not trying to offend. Good Luck

  25. #25
    Lieutenant Commander flashback's Avatar
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    Default Re: Ford 302 from 2 barrel to 4 barrel, is it worth it ?

    Well Valv, I guess we have gone full circle here, let us know what you decide to do........good luck
    The Devil to pay, and no pitch hot!

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