This 350 is driving me nuts...

Discussion in 'Small Block Tech' started by 70skylarkcusto, May 5, 2022.

  1. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    Just a fairly stock Buick style q jet from 74 I believe. Had it professionally rebuilt once. He put everything back to factory settings. I even brought the car to him to try to have him adjust the carb. He had no luck basically told me “something is going on and I can’t figure it out, sorry I’ve done as much as I can” granted he’s not a performance build type place, he’s just a rebuilder. Great for a stock rebuild but not sure he really knows how to power tune those carbs
     
  2. LARRY70GS

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

    And that is the mistake most make with Quadrajets. The reason they are maligned most often is someone puts a Quadrajet, any Quadrajet, on an engine and expects it to run right despite it being calibrated for a different engine. As soon as you change the cam, at bare minimum, the carburetor idle system needs to be modified. I suggest you see what the part number is. Then get in touch with Ken Gies and see what he advises.
     
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  3. Reidk

    Reidk Well-Known Member

    Man I sure hope you can get it figured out. Totally sounds like it could be ignition related too. You mention God up on your signature...dont let the stress of these material things drag you down. Were meant to enjoy this earth and the things in it but I personally fell into a sinful obsession with my car last year. Larry actually told me a couple of times to just walk away from it for a while. I tried but I was obsessed. Sounds like you have been dealing with this for several years hopefully you aren't letting it get to you every day. Thinking back I was selfish and it started to piss my wife off... true "other woman" type scenario going on.
     
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  4. Fox's Den

    Fox's Den 355Xrs

    Larry has it exactly right with his comments, when I had the TA510 cam in even though I had the 3500 stall convertor in there and a 373 gear and 10.6 compression coming out of the hole with the 750 dbl pumper was a problem and I really had to work on it to get it somewhat responsive in the 60 ft that cam only had 5 inches of vac.

    I really needed a 4000 stall or a set of 411 gears, because my 60 ft suffered 1.90 but once I got the rpm up it started to roll. It would pull past 6 grand with that cam easily. I went with a smaller cam after that and went a little faster but the 60 ft was a lot quicker. I could now get out front on some of those stock 455's and take them out,sometimes, lol.

    That being said the 256 gear and that big carb are not living together, That is why the 600 carb is more responsive smaller venturies quicker response.
     
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  5. Reidk

    Reidk Well-Known Member

    Just to be clear, I 'm not suggesting he try a 600 with that dual plane. My suggestion to him was to try a double pumper. Not sure I'd go with a 650 or 750 though. I do feel like the 350 is constantly being over carbed....so maybe a 650
     
  6. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    Thankfully reidk, I did take a little time away from the Buick, worked on some other projects, spent some time with friends and family. Didn’t let it beat me down or drive me to the point of obsession, but now I am determined to figure it out. If not, give up and start over
     
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  7. Fox's Den

    Fox's Den 355Xrs

    The 350 Buick used a 750 cfm Q-Jet on their engines. Most all larger carbs used on the engine from what I have seen always upped the HP on the motor. You put that 373 gear in that car it will want that 750 carb.

    Go to the track to prove this and not the burn outs, seat of the pants, or anything else that makes you think the car is faster.
    On the top end the 600 carb will be passed by the 750 carb no matter what happens in the starting line.
    I used to do 1 wheelie peelies with my 650 dbl pumper spreadbore with the 256 gear but it was a b to get it out of the hole and I knew nothing about a carb then. Ran 16 second times with that 256 gear ran 14's with the 373 gear.
    The low gears and the larger carb and the bigger cam kills the signal from the carb to start up.

    Everytime I went to the track and I thought it ran faster it was always false.
    It only runs faster in the 3rd round when you breakout.lol
     
  8. Reidk

    Reidk Well-Known Member


    Maybe try a new PCV valve. you can get one of these adjustable ones. They have solved issues for other guys with similar problems. I just remembered this tonight. I stumbled across these when I was doing a little research. If you don't want to go this route you can call your local parts store tell them you're working on some performance car... you can make up anything... tell them you need a PCV valve for like a '70s Corvette. It will be different than what would have came in a 1985 smog vehicle. They aren't all the same. I know in some cases they can really smoothen out your idle and bring vacuum up. Doubt it would help with coolant temp though.

    https://www.classicindustries.com/p...TXVZha8jQjnxi_Wr8KxoCUGgQAvD_BwE&gclsrc=aw.ds
    https://www.motortrend.com/how-to/tunable-pcv-valve-fixes-cruise-woes-engine-leaks/
     
    Last edited: May 9, 2022
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  9. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    funny you mention, I did have a vacuum leak from the pcv when I first fired up the engine. I did replace it. But only with a cheap dorman pcv. I did test it before Install. So I do know it works but will check this out too! Thanks
     
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  10. Reidk

    Reidk Well-Known Member

  11. patwhac

    patwhac Well-Known Member

    I have one of the ME/Wagner adjustable PCVs and I like it so far, but my engine has only been run on the stand so no real world driving data yet. Sure is purdy though!
     
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  12. Reidk

    Reidk Well-Known Member

    You might be one of the only success stories I know of when it comes to this camshaft being used in a 350. Do you have an afr gauge? How do your plugs look? Can you roast the tires? A 300 + horse power motor should fry the tires especially with a stall converter. How's it do in stop and go city traffic?
     
  13. 70skylark350

    70skylark350 Jesus loves you unconditionally

    What cam would you suggest, the 212? My only comparison is the stock motor that I replaced so maybe it’s not performing up to par? I may actually have a cam issue with my motor now, possibly flat lobe, so this cam may be coming out anyway.
     
  14. Fox's Den

    Fox's Den 355Xrs

    I would stick in the 212
     
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  15. Reidk

    Reidk Well-Known Member


    Yes the 212. This discussion has been going on for decades. Unfortunately I didn't do enough research in 2020 when I did my rebuild. Just google search (284-88h v8buick.com) it will pull up several threads. BUT you seem to have a decent combo with this cam that's why I was asking about the other details. My car runs pretty good now but I think the 212 would be a huge improvement.
     
  16. sean Buick 76

    sean Buick 76 Buick Nut

    Use a dial indicator on each rocker to see if each cam lobe has full lift. Crank the engine by hand
     
  17. Brian Albrecht

    Brian Albrecht Classic Reflections

    Did you try backing off initial, I assume you have?

    Totally agree with the notion exhaust may not be scavenging properly. Thats why I asked about what the Hooker's are dumping into, but it hasn't been answered as of yet. Hit the track or drive around uncapped to see what that does?

    Cooling system and/or improper scavenging of exhaust gases.

    This cam grind ( or combination of valvetrain ) maybe the reason for the improper scavenging.

    Sure couldn't hurt to try, did you?

    This would eliminate any individual cylinder issue and wouldn't cost you anything.

    Also. Op, you mentioned another set of heads laying around. I might consider trying those as is before removing the cam. Exhaust all options, lol.

    Three fifties are strong out of the hole. You should be able to do a decent burnout.
    Especially with 3.42's!
     
    Last edited: May 22, 2022
  18. LARRY70GS

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

    Not sure what you are asking. When Jim built my 470, he used my AED 1000 to Dyno it. He also modified my 7042240 QJ using one of Cliff Ruggles' recipes so that it would work with my engine. It's perfect, idles great, and is seamless everywhere. I have run 11.60's with it, and I have done as well as 16 MPG with it on the way to Cecil one year. Ken Gies also built me a QJ as a carburetor for my engine, that I keep as a spare.
     
  19. LARRY70GS

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

    OK, since you quoted me, I thought you were asking me.
     
  20. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    I had tried backing off timing, setting it anywhere between 10 and 16 degrees. Never seemed to detonate when advance, but didnt help how the engine ran.
    The hookers are dumping into a 3 inch collector reducing down to 2.5 inch Pypes exhaust with street pro mufflers
    Valve train is stock 1.55 ratio
    I have a rebuilt carb with modification for my set up in the mail as we speak and will throw it on this weekend and find out!
    Have not tried the dial indicator on the rockers but I have seen all valves moving freely and seemingly completely
     
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