How to offset your air cleaner base, maybe something for B4B/GS hood guys

Discussion in 'Wrenchin' Secrets' started by 1972Mach1, Dec 16, 2020.

  1. 1972Mach1

    1972Mach1 Just some M.M.O.G. guy.....

    Was just in another thread and I was getting it off topic a little with how to do this, so I figured I'd do a thread down here about the process. Since I'm at work and it's winter, I'm going to do some paper demonstrations.

    First of all, you need an air cleaner base with a flat inner surface, because you're going to be cutting it and rewelding it. There's quite a few out there, if needed I can get you a link, but I'll include a pic of one from eBay that is already offset. Even though it's offset already, you could still put the carb opening anywhere you need it to be, even back to the center.

    First order of business, obviously, is you need to figure out where you need your carb to be in relation to the base, and you need to mark the center of it. You need to figure out how far that is from where the center of the carb hole is currently and the distance between the two. Find something that is circular with a diameter slightly larger than the carb hole (5 1/8" is the common size) and make your first cut line slightly outside of the carb hole. Making it centered over the top of the hole is easiest for math, but not necessary as I've done here in my paper model. Then put your circular line maker over where you need the center of the carb to be on the base. If you centered the hole both times, all you need to do is connect the widest part of the circles you drew with straight lines.

    Next, cut your circles and lines (which should be an oval) and remove that part of the base. Flip it 180 degrees. Weld/braze in place. Done.

    (If my words were confusing, which I'm sure they were, look at the pics) :D

    base4.png base5.png base6.png base7.png base8.png
     
    Cutlass likes this.
  2. 1972Mach1

    1972Mach1 Just some M.M.O.G. guy.....

    Oh, and you'll need to make a new stud. Just use ready rod.

    base.png base1.png s-l1600.jpg
     
  3. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I always wondered if an oldsmobile base would be a good donor. The HEI distributor requires an offset base to clear the cap on the olds engine..
     
    1972Mach1 likes this.
  4. 1972Mach1

    1972Mach1 Just some M.M.O.G. guy.....

    Might be, Joe. I said it in the other thread, but I've never owned a GS (although my family has) and haven't a clue what the offset would be to make the air cleaner work with a B4B and GS hood. Just thought I'd throw out an idea for someone to try that might be something beneficial for all the guys that do want to run that intake on their 70-72s with the scoops and GS air cleaner. Once someone figures one out, they could give out the base and measurements. If I had someone's car to mess with, I'd figure it out and post the results.
     
    Last edited: Dec 16, 2020
  5. Brandon Cocola

    Brandon Cocola Well-Known Member

    This thought crossed my mind and I may have to try it but currently my 455 is 20 miles from the skylark and the GS hood is 6 feet from the car and the B4B is in the trunk so my measurements may be a little off. My cousin car that is all together is in storage.
     
  6. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I think the B4B is off an inch. One could probably just shut the hood and live with it. Denny Manner said the scoops were put on for the marketing department and did little for performance, so we might be splitting hairs..

    On a side note, on a 70 scoop only about 1/2 the scoop grates are open. I wonder if opening the rest of the grates would improve performance?
     
    ilikebmx999 likes this.

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