Check your Edelbrock Air Gap Manifold! If you have one - read this.

Discussion in 'High Performance Modifications' started by 71RS6SPD, Nov 26, 2017.

  1. 1980RS

    1980RS Veteran Member

    1,591
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    Jun 17, 2006
    Get out the die grinder and clean it up. Edelbrock won't help you at all. I still think their machining has gone down hill to back to where it was in the late 70's with them. There was a lot of poorly machined stuff back then.
     
  2. 71RS6SPD

    71RS6SPD Veteran Member

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    4
    Nov 14, 2016
    That's just what I did! Cleaned it up to match spacer. I also noticed the spacer can shift on the studs. Did not like that so I bought some small o-rings for the carb studs. They fit right up into the spacer sleeves and center the bolts - not just to mount is correctly but also when I machined it a bit I wanted to make sure I was cutting where I should. I opened the top of the manifold to remove all obstructions to flow and shrunk the width of the divider a bit so it is in the middle. I went a little further too and cleaned up the overly rough spots in the intake ports. I also plan to use the additional cooling ports for the rear of the heads - hence the thermostat spacer.

    One recommendation I will make is to always wash manifolds before installation. Both new and old. There was plenty of something in the manifold before I touched it. I ran my finger inside a runner and it came out dirty. This may be alum dust/sand I do not know but it was not clean out of the box.

    Just about ready to install now.. next week probably. IMG_20171207_165725118.jpg IMG_20171207_161514202.jpg IMG_20171207_163348236.jpg
     
  3. camaro71/holland

    camaro71/holland Veteran Member

    849
    16
    Aug 27, 2003
    The Netherlands
    So the spacer fitted over the o-rings on all four corners? That sounds very loose...
     
  4. 71RS6SPD

    71RS6SPD Veteran Member

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    Nov 14, 2016
    .
    It's actually the way that most aluminum spacers are. There seems to be about 1/16th of movement in the spacers (5/16" bolts and 3/8" holes). They are small 1/4" thin o-rings. At first I did not think of them sliding up into the spacer and I was about to chamfer the bottom of it to give them room when I noticed they fit in snugly. Just put them on after the gasket where the pict shows and slide the spacer over for a precise fit. No lube required. I bet the carb has similar movement too but it's less important as the barrels are smaller than the opening - for a 650 anyway. Maybe an 850 is similar in size?
     
  5. 1980RS

    1980RS Veteran Member

    1,591
    11
    Jun 17, 2006
    That nice job looks like 15hp to me.
     
  6. 71RS6SPD

    71RS6SPD Veteran Member

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    Nov 14, 2016
    Thanks, I will probably feel the 15 even if it's not there lol. It was worth the effort just for peace of mind. Can't wait to see if the dual plane adds more mid range I can easily feel in my butt. Traction problems will get worse hopefully!
     
  7. 1980RS

    1980RS Veteran Member

    1,591
    11
    Jun 17, 2006
    It will if you use that 4 hole spacer, the open one will make more top end.
     
  8. 71RS6SPD

    71RS6SPD Veteran Member

    143
    4
    Nov 14, 2016
    I've been debating on which spacer insert to try first. Will try both. It's a cool spacer for 30 bucks. I am looking forward to see if there are measurable performance and tuning differences between the 2 inserts. I have a new wide band O2/afr guage and it's awesome for tuning a carb. I still want injection though. I am planning to buy another spacer kit just to get spare inserts I can modify. I want to make a third custom spacer with tapered 4 hole to open like one of those 200 dollar pieces.
     

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