350 intake compatibility

Discussion in 'Small Block Tech' started by v8regalowner, Jun 22, 2018.

  1. v8regalowner

    v8regalowner Silver level contributor

    I know this subject has been covered on here before but I can’t seem to find it. I sold a 69 350 4 bbl to a friend for his 76 regal. The shop he had it at couldn’t figure out how to switch everything over so they put the 76 intake and the rebuilt 69 qjet on it. I thought I saw somewhere that it was a no no. They got it running but he said it’s got less power now which tells me they did something wrong. He’s going to bring it to me to take a look at it. Figured I may end up having to switch the intake back for him.
     
  2. alec296

    alec296 i need another buick

    69 engine with a 76 intake? Intake gasket is probably wrong . Choke may not be pulling off enough to unlock secondarys. They may have a vacuum leak or wrong baseplate gasket. Or set timing and vacuum advance wrong. Either way he should make them fix it.
     
  3. v8regalowner

    v8regalowner Silver level contributor

    Thank you. I was thinking many or the same things. Just waiting to get my hands on the car. When he told me they even changed the intake because they couldn’t figure out how to hook everything on the car up I knew there was going to be issues. I have a feeling the shop doesn’t have a clue how to work on old cars.
     
  4. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Yeah, most mechanics are paint by numbers guys that need to work with a manual.

    You'll probably want to read up on the power timing thread because if they set the timing by the '76 "book" then there is a whole lot of power right there left on the table. As far as I know all the factory 4bbl boat anchor intakes should perform about the same so you might not have to swap the intake if you can get the thing tuned in for him?

    An air/fuel gauge would be good to have as well to make sure the carb is right too. GL
     
    MrSony likes this.
  5. v8regalowner

    v8regalowner Silver level contributor

    So I finally got the car so I could take a look at it. Starts runs and idles beautifully But I believe there is a vacuum leak and I believe the secondaries are not opening on the qjet. Usually you can hear the qjet sound like it wants to suck the hood in when they open on every other one I’ve owned and there is nothing. No matter which vacuum line I unhook the idle never changes and the timing is off the scale on the timing cover. I plan on retiming it but I figure it’s useless until I figure out if there is a leak.
     
  6. MrSony

    MrSony Well-Known Member

    With the car off go under the hood with the air cleaner off and physically open the throttle. Keep it open and push the air valves open and see if the secondaries are open below. If they are, the air door tension might be too tight and isn't allowing them to open on time or at all. There is a 3/23 allen set screw and a small flathead adjustment screw on the rear passenger side of the carb. Undo the setscrew, turn the adjustment screw to where the doors basically have no tension on them (may even flop open and stay down), then tighten the adjustment screw until you see it just catch the doors and start to close them, then do another half turn. Tighten the set screw, then after timing it, go for a drive. Mat it, if it goes b-b-b-WAAAA, doors are too loose. Tighten 1/8 to 1/4 turn at a time, little adjustments make a big difference. over 1 turn will usually deform the spring and it will lose it's "springiness". Make sure your kickdown is working properly as well. With the carb all the way open, the cable should be at full extension. No more, no less.
     
  7. MrSony

    MrSony Well-Known Member

    Vacuum gauge will tell if you have a leak.
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Cable might be wrong. Have someone mat the gas pedal with engine off, then look to see if the secondary throttle plates are open.
     
  9. alec296

    alec296 i need another buick

    It’s probably a choke lockout . Weak choke pulloff
     
  10. v8regalowner

    v8regalowner Silver level contributor

    Going to pick up a vacuum gauge tomorrow. Thank you as always everyone. I’ll keep you posted
     
  11. Mark Demko

    Mark Demko Well-Known Member

    Honestly I cringe when I hear of people taking their older (way older) car to a "mechanic"
    I don't want to make a blanket statement, but a lot of "techs" today don't understand how stuff works, oh, they know their way around a computer/scan tool, but that stuff isn't the do all /end all of automotive diagnosing, they need to know the how's and why's.
    Theres a lot of skilled trades today going by the wayside, its sad, and its not the way things should be, when stuff breaks, younger people will all stand around looking at each other, then along comes the "old timer" who understands the why's and how's:D
     
    MrSony and Dwayne B like this.
  12. agetnt9

    agetnt9 Agetnt9 (Dan)

    I must be an old timer then ........................ Ha and love showing kids the why for.
     
    Mark Demko likes this.
  13. v8regalowner

    v8regalowner Silver level contributor

    Well the mystery is solved. Secondaries wernt opening because the little lever on the passenger side wasn’t letting them. Still not exactly a drag car but running much better. I think there is more in it still but I think he is going to need some gears to find it. Thank you all for your help as always.
     
    MrSony likes this.

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