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Technical Just how much HP will a 4 bbl add

Discussion in 'The Hokey Ass Message Board' started by junkyardjeff, Sep 13, 2016.

  1. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 8,588

    junkyardjeff
    Member

    Yesterday I found the HP and torque figures of a 59 Olds 371 I had years ago,270 horses and 390 foot pounds of torque and it only came with a 2 bbl. Well I could not leave it alone and added a 4GC and intake from a 59 394 and it perked up some more so I was wondering how much HP would be added to putting a 4 bbl on that motor,I had that motor in a 53 super 88 2 door sedan and late model corvettes and a few hotrods seen my tail lights back in the mid 80s and wanting to find another and do it over again.
     
  2. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,213

    sunbeam
    Member

    From old motors manual a 58 Olds 371 came both ways 2 barrel 265 hp 4 barrel 305 hp compression ratio was 10.00 on both motors.
     
  3. JeffB2
    Joined: Dec 18, 2006
    Posts: 9,484

    JeffB2
    Member
    from Phoenix,AZ

    I would be a little skeptical about a 40 HP gain with just the 4 barrel only,probably a litlle better cam and dual exhaust. If you keep your foot out of the back barrels the smaller primaries in the 4 barrel might gain some MPG over the 2 barrel when cruising.
     
    lothiandon1940 likes this.
  4. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 8,588

    junkyardjeff
    Member

    59 371 was a 2 bbl only motor so no specs in my Motors manual for a 4 bbl, the 59 394 was 315 hp and 435 torque. I am just curious how much more hp a 4 bbl would have given this motor,it was the best running motor I ever had in any of my cars.
     

  5. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    1959
    Dynamic 88 V8 371 9.75 compression,... 270 hp@ 4600,torque 390 @ 2400

    Super 88 V8 394 9.75 comp,....315 hp @ 4600 435 torque @ 2800

    98 V8 394 9.75 comp,......315 hp @ 4600 435 torque @ 2800


    The 371 shows max torque at lower RPM than the 394 4 barrel. I think same stroke?, so maybe this shows that the 371 was undercarbed?
     
  6. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,213

    sunbeam
    Member

    From a carb CFM calculator @ 83% volumetric efficiency at 3500 rpm a 371 would need 311 cfm. A small pattern 2GC won't flow much more than that.
     
  7. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,795

    jimmy six
    ALLIANCE MEMBER

    Not to be picky but they are engines you start with electric motors. As an old power plant electric it just drives me crazy. When guys ask which "motor" I have, I tell them 1.4 kw for the starter.:p
     
  8. buffaloracer
    Joined: Aug 22, 2004
    Posts: 816

    buffaloracer
    Member
    from kansas

    I'm guessing that with dual exhausts that 40 hp us fairly close.
     
  9. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    FAIL ..... :

    "motorcycle"
    "Happy Motoring"
    "Indianapolis Motor Speedway"
    "Motor Vehicle Department"



    should I keep going? I'm busy today :)



    .
     
  10. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Man, the ones with three rochesters must have been awful, eh?:rolleyes:
     
  11. :D I have been called motor mouth before.:D

    Engine, motor, mill, bolt, power plant, on a good day I could maybe come up with a couple more. Good conversation is often doted with colloquialisms, and the meaning is more often than not determined by context.

    OK so much for the world according to the Beaner. A simple new carb probably won't add much in the line of HP or torque unless it was under or over carbed to start with. It is when you start carving out ports, changing bore and stroke, cam shafts and compression that you start making a real difference in numbers.
     
    town sedan likes this.
  12. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,263

    gimpyshotrods
    ALLIANCE MEMBER

    Then leave it alone.
     
  13. J. A. Miller
    Joined: Dec 30, 2010
    Posts: 2,057

    J. A. Miller
    ALLIANCE MEMBER
    from Central NY

    Ford Motor Company
    General Motors
     
  14. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 31,174

    Jalopy Joker
    Member

    so, if you switched to a 4 barrel manifold with upgrade(?) 4 barrel carb & have dual exhaust 30+ HP may be the result. bottom line, just go out and enjoy the ride. don't sweat the little details
     
  15. caton462
    Joined: Jul 17, 2013
    Posts: 176

    caton462
    Member

    Rule of thumb for my experience. High torque 2 barrels with 9:1 or higher compression gain 30-40 hp. Low torque 2 barrels with less compression ratio do not see much change or even lose performance. Would not do the change without freeing up the exhaust as well.
     
  16. oldolds
    Joined: Oct 18, 2010
    Posts: 3,407

    oldolds
    Member

    Looking on this chart I suspect 20hp.That is on a 394 base 2bbl compared to smallest 4bbl
    http://www.carnut.com/specs/gen/olds60.html

    1963 155 H.P. F85 V8-215 2 Barrel 3.5 x 2.8 215 8.75 155 @ 4800 210 @ 3200 30 AC 46FFX .030 .019 30 18436572 5°/7° auto -12
    185 H.P. F85 V8-215 4 Barrel 3.5 x 2.8 215 10.25 185 @ 4800 230 @ 3200 30 AC 45FF .025 .019 30 18436572 7 1/2° -12
    195 H.P. F85 V8-215 4 Barrel 3.5 x 2.8 215 10.75 195 @ 4800 235 @ 3200 30 AC 44FF .030 .019 30 18436572 7 1/2° -12
    215 H.P. F85 V8-215 1 Barrel 3.5 x 2.8 215 10.25 215 @ 4600 300 @ 3200 30 AC 45FF .025 .019 30 18436572 10° -12
    260 H.P. V8-394 2 Barrel 4.125 x 3.688 394 8.75 260 @ 4400 410 @ 2400 35-45 AC 45 .030 .019 30 18736542 2 1/2° -12
    280 H.P. V8-394 2 Barrel 4.125 x 3.688 394 10.25 280 @ 4400 430 @ 2400 35-45 AC 44 .030 .019 30 18736542 -12
    330 H.P. V8-394 4 Barrel 4.125 x 3.688 394 10.25 330 @ 4600 440 @ 2800 35-45 AC 44 .030 .019 30 18736542 -12
     
  17. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,213

    sunbeam
    Member

    I'm thinking 900 cfm will feed almost any thing under 400cu.
     
  18. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    I'm really glad you aren't doing my thinking for me...;):)
     
    CowboyTed likes this.
  19. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,530

    Dan Timberlake
    Member

  20. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,530

    Dan Timberlake
    Member

    In the 1955 SAE paper about the new small block V8 hp and torque curves were published for the 2 and 4 bbl versions of the 265. cnevy SAE HP and torque 2 bbl 4 bbl aligned 16 color overlay.jpg
     
  21. Grumbler
    Joined: Mar 2, 2009
    Posts: 358

    Grumbler
    Member

    Thank you!!! Pet peeve of mine, I'm in aviation and that's the way it is, you've never heard of a turbine motor hung on an airplane (at least I hope not) it's turbine engine, or if old school, reciprocating engine! Here's another one for you guys, the environmental system on an airplane is the air conditioning system, period. You're either heating the air or cooling it, so no matter what, you're *conditioning* it, correct? I don't expect any converts, just had to get that off my chest LOL. Sorry for the hijack, back to regular programming..........
     
  22. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,213

    sunbeam
    Member

    I'm a slow learner you win George you are always right.
     
  23. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,791

    tfeverfred
    Member Emeritus

    What did HRM say?
     
  24. The amount of power a 4bbl can add is directly proportional to the amount of restriction of the 2 bbl. that restriction depends on a whole bunch of stuff that's not directly connected to the carb
     
  25. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    you know when to fold, I'll give you that...:D
     
  26. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 8,588

    junkyardjeff
    Member

    That engine was quick with the 2 bbl and the 4 bbl did help it some,now to find another 59 371 that runs or could be running with a little work. The last one I bought was in a 50 dollar parts car back in 85 that sat for a couple years and I had running in a hour but I do not think its going to happen like that now,if I can find one it will go in a 2 door hard top this time or something lighter.
     
  27. You can't cool air - what is happening is that the heat is being removed from the air.
    Adding heat is easy, any type of heat energy is sucked up like a sponge into anything that's colder-it's The natural flow heat. Removing heat is always an involved process requiring a whole mess of conditioning processes to get it there requiring so much more since it's usually done when everything around is plenty hot.

    One sided thinking leads to a mental scotoma and simply eliminates the multitudes of motor references. Listing them all won't help, it will probably enforce the belief that everyone else is wrong. I can 100% guarantee there are more references to "motor" than "engine".
     
    shawnsauto1 likes this.
  28. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Jeez, I had to google that! Sounded a little like "scrotum" kinda scared me a little...
     
  29. You should be scared of it,
    It's a "Lock on and lock out" phenomenon that negates every fact presented because the single belief (many times completely false but generally corrupted) has a powerful grip. It's considered truth, it's considered to be an unwavering constant even though it's wrong.
    You don't want one :p:p:p
     
  30. CowboyTed
    Joined: Apr 27, 2015
    Posts: 343

    CowboyTed
    Member

    That was my thought too. Far too many teenagers add a four barrel to "open up" their engine without any other mods, and wind up with an engine that makes less power, but more intake noise, than the one they started with. The intake noise makes them believe their car is now more powerful.

    Heck, I once increased the horsepower of my old Camaro just by turning the air cleaner lid upside down. It sure breathed better. You should have HEARD it! (If you can't laugh at yourself . . . ) ;)
     
    Last edited: Sep 14, 2016

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