318 Two to four barrell advice

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    Author Topic: 318 Two to four barrell advice  (Read 9460 times)

    Offline Road_Runner

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    Re: 318 Two to four barrell advice
    « Reply #30 on: March 10, 2010 - 12:21:47 AM »
    Quote from: Chryco Psycho on August 05, 2009 - 01:09:35 PM
    an LD4B is the best bet if you can find one , that & the later 318 in the late 80s are the only small port 318 intakes I am aware of , the last one I did we used the very small 570 Holley Avenger carb

    How does the Mopar M1 Dualplane manifold's ports match up to the 318?  Mopar Performance shows this as a 'stock' replacement but that probably doesn't mean a whole lot.  Since I've picked up a 340 short block I may not even bother with the 4 bbl on the 318 and just drive it as is if I can get the 340 together in the next year or so.  Based on alot of the advice around here, I'm strongly leaning towards an Edelbrock Performer RPM on the 340.
    Thanks, Jim
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    Offline Chryco Psycho

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    Re: 318 Two to four barrell advice
    « Reply #31 on: March 10, 2010 - 04:16:37 AM »
    no the M1 dual plane has the larger 340/360 port size
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    Offline thesado

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    Re: 318 Two to four barrell advice
    « Reply #32 on: March 10, 2010 - 11:35:53 AM »
    Quote from: Chryco Psycho on March 08, 2010 - 12:05:04 PM
    you will need a 20-7 linkage adapter for the carb

    Thanks for the tip CP.  I got it ordered.  :thumbsup:
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    Offline thesado

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    Re: 318 Two to four barrell advice
    « Reply #33 on: March 10, 2010 - 11:52:21 AM »
    Should I use a carb spacer?
     :clueless:
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    Offline 71chally416

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    Re: 318 Two to four barrell advice
    « Reply #34 on: March 10, 2010 - 11:41:55 PM »
    Quote from: thesado on March 10, 2010 - 11:52:21 AM
    Should I use a carb spacer?
     :clueless:

    They usually improve performance. On my old 318 I tried different spacers at the track and it liked an open spacer with a divider in between on the LD340 Intake I used that had the divider wall cut down as recommended in the race manual. In other words, the left and right banks were then seperated as the LD Intake is stock. I would use a 4 hole 1" thick spacer.  :2cents:
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    Offline thesado

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    Re: 318 Two to four barrell advice
    « Reply #35 on: March 19, 2010 - 01:28:36 PM »
    OK, I tore into my car yesterday.  The inside of the engine looks perfect!    :working:  Not going as planned though.  I'm having trouble deciding if I can reuse the intake gaskets or not, the air cleaner hits the throttle (getting a different one), and none of the linkages will fit. :(  What am I supposed to do to get these linkages to fit?  I thought this was a drop-in conversion.  :bricks1: :pullinghair:
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    Offline Chryco Psycho

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    Re: 318 Two to four barrell advice
    « Reply #36 on: March 19, 2010 - 07:14:29 PM »
    If you use the 2 bbl throttle bracket you can make a small link from the cable out to the throttle pin on the carb & if it is a 3 piece kickdown link you need to extend the upper link or put a bolt in the slide to make it go all the way back , a 14" drop base A/C should fit without interfering with the throttle arm
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    Offline Road_Runner

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    Re: 318 Two to four barrell advice
    « Reply #37 on: March 19, 2010 - 11:55:29 PM »
    Quote from: Chryco Psycho on March 10, 2010 - 04:16:37 AM
    no the M1 dual plane has the larger 340/360 port size

    I think I asked this in another thread, but just so I'm sure: What do you think of the M1 dualplane for a moderate 350 hp or so 340 compared to what appears to be everyones favorite Ede Performer RPM dualplane?  I'm in the gathering parts stage for the 340 build.  What I'm thinking is stock stroke, no more bore increase than is required to true the cylinders, either Ede aluminum or RHS/Indy iron heads, cam(?) and either 340 TA exhaust header/manifolds or headers.  Any thoughts on this combo?

    Thanks, Jim
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    Offline Chryco Psycho

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    Re: 318 Two to four barrell advice
    « Reply #38 on: March 20, 2010 - 02:12:42 PM »
    I would try it without the spacer first althougha spacer may help , different types of spacers do different things as well
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    Offline Chryco Psycho

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    Re: 318 Two to four barrell advice
    « Reply #39 on: March 20, 2010 - 02:18:35 PM »
    Quote from: Road_Runner on March 19, 2010 - 11:55:29 PM
    I think I asked this in another thread, but just so I'm sure: What do you think of the M1 dualplane for a moderate 350 hp or so 340 compared to what appears to be everyones favorite Ede Performer RPM dualplane?  I'm in the gathering parts stage for the 340 build.  What I'm thinking is stock stroke, no more bore increase than is required to true the cylinders, either Ede aluminum or RHS/Indy iron heads, cam(?) and either 340 TA exhaust header/manifolds or headers.  Any thoughts on this combo?

    Thanks, Jim
    there is a lot of variables here , I would use a Lunati Voodoo cam if you want a hyd cam , there are a few to pick from so match the real powerband you want the engine to work in . You want to alter the cam grind between headers & manifolds , I would use a 110* CL with headers & a 112* with manifolds . if you go with headers use the TTI or Dougs that stay above the steering link .
    The M1 is the factory 340 intake which works very well , you will see some powergains using the RPM AirGap though .
    Personally I would stay away from the Eddy Alum heads , you need to be in the 11:1 compression range to use them meaning you need a dome piston which hurts flame travel in the engine , I would lean towards an Iron head like the RHS & 9.8:1 compression with a flat top piston
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    Offline thesado

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    Re: 318 Two to four barrell advice
    « Reply #40 on: April 07, 2010 - 01:28:38 PM »
    Just a little update on the progress here.  I got everything fabed/painted/installed, got it running and started on the tuning.  It was running rich and lacked any sort of power.  In fact, it seemed like it had less power than it did before the 4bbl.  I pulled the bowls to check the jetting and it had 67s in the front and 73s in the rear (it was on a racing motor).  I put 70s in the front and it runs much better.  This was last night so I have yet to really see if it's going to be right or not.  Any suggestions on jet sizing for this?

    I also tried to set the timing.  I assumed 15° BTDC at idle would be close, but that put me up to 47° at around 3500 and a bit of pre-detonation.  Tried it at 5°/36° which was terrible.  Ended up dialing it to 11°/41° where it runs much better.  I'm still not sure that's right though.  Thoughts?  I'm thinking the springs in the dist might be worn out. ???

    Since the tuning it now feels like it has more power than the 2bbl, albeit, not much.  It does run a bit smoother though.  Also, I can't feel any increase when the secondaries kick in.  There must be something I'm still not getting tuned correctly, or the jets are just wrong.

    And lastly, I hooked the PCV valve up (to the carb base) and it pulsates like CRAZY!  Very loud inside the car.  I read that the orifice size is tuned to the engine.  How can I either get it to stop pulsating or quiet it down?

    Info: It's a Holley 650 dbl pumper. No power valve or mixture adjustments on the secondaries.  Float levels have been set. Idle mixture is currently 1.5 turns out on the primaries. Idles around 700.

    I'm pretty unsure here.  Thanks for any advice!
     :newbie:
    « Last Edit: April 07, 2010 - 01:34:08 PM by thesado »
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    Offline MEK-Dangerfield

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    Re: 318 Two to four barrell advice
    « Reply #41 on: April 07, 2010 - 03:25:20 PM »
    Before you start playing around with the jets, take a look at a spark plug or two. That should clue you in if you are rich, lean, or close to ideal.

    Is your PCV valve made for a Mopar, or is it a generic replacement? I've never heard one rattle that loudly before.   :screwy:
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    Offline thesado

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    Re: 318 Two to four barrell advice
    « Reply #42 on: April 07, 2010 - 03:37:43 PM »
    MEK, I pulled one yesterday before and during adjustment.  I could see the lean burn and pre-detonation.  I'll be pulling it again soon after I get a few miles on the new settings.

    The PCV is a generic replacement for a stock 318, but "interchanges" with literally dozens of other engines.  I installed just a couple of years ago and it's still clean.  I have the option to get an ACDelco unit but didn't want to waste the $$$ if it's not the problem.
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    Offline Aussie Challenger

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    Re: 318 Two to four barrell advice
    « Reply #43 on: April 08, 2010 - 06:41:14 AM »
    When you are setting the timing the vac advance should be disconnected, you really don't want much more than 34* - 38* max, 1.5 turns is a good starting point for the idle but you need to fine tune the idle screws once the motor is running. I have heard some generic PVC valves rattle badly when the idle is not right.
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    Dave

    Offline Chryco Psycho

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    Re: 318 Two to four barrell advice
    « Reply #44 on: April 08, 2010 - 11:02:47 AM »
    Measure your vacuum idling in gear first & installl a powervalve with at least a 2" lower rating , typicaly Holley uses a 6.5" power valve
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