Who is going fast with the stock 3/8" fuel lines and Stage 1 pump?

Discussion in 'Street/strip 400/430/455' started by rkammer, Jun 25, 2020.

  1. rkammer

    rkammer Gold Level Contributor

    So, I'm going through my entire fuel system from tank to carb. I'm staying with the stock 3/8" fuel lines and Stage 1 fuel pump but upgrading the tank sender to 1/2 " (without the sock) and replacing all the rubber lines up to the fuel pump. Also installing a free flowing billet filter before the Stage 1 pump which feeds an 800 CFM Quadrajet. I'm hearing that my 468 HP 455 should probably go to 1/2" lines and a better mechanical pump but am hoping the stock setup will suffice.

    So, here's the question. How many of you guys with 455s are going fast with the stock fuel system? I'll define fast as at least 108 MPH & under 13 seconds in the 1/4. Let's hear some times. (Remember, only 3/8 lines and stock Stage 1 pump - no pushers).
     
    Last edited: Jun 26, 2020
  2. BUQUICK

    BUQUICK I'm your huckleberry.

    My '67 GS convertible ran 12.10 @ 111.39 with a stock fuel system (original fuel lines and original pickup in the tank) and a Stage 1 pump. Engine is all stock appearing cast iron and the race weight is 4,000 pounds. I later added an electric pump to push from the rear with zero improvement. I suspect my car only makes about 430 hp so the stock fuel lines, pickup, and Stage 1 pump are apparently still plenty for a car at this level. I do however have to run at least 1/2 tank of gas.

    Rest of the car:
    -Stock appearing '67 GS convertible, dented, faded, and a little rust
    -455 bored .030", sealed power pistons, rue compression is 9.98:1, ported heads, intake and exhaust manifolds, stock rocker arms, 230/240 cam with .496" lift, 800 cfm Q-jet with .073" primary jets and .041" secondary rods, stock distributor with points, MSD box under the front seat.
    -ST400 transmission with a swith pitch converter from a ST300
    -8.2" rearend with 3.55 gears
    -2.5" exhaust with Walker 17295 mufflers (no x-pipe, no h-pipe, and front section of the exhaust was not mandrel bent)

    stock.jpg
     
    Last edited: Jun 26, 2020
  3. johnriv67

    johnriv67 Well-Known Member

    You MUST specify if you are using a Quadrajet or a Holley. Holley’s are much more forgiving with their dual fuel bowls. You need more pump on a Quadrajet, or something blocking the return line.
     
    ranger likes this.
  4. GS Spoken Here

    GS Spoken Here Well-Known Member

    7.45 in the 1/8, Holley with a pusher pump back by the tank, all line is 3/8"
     
  5. rkammer

    rkammer Gold Level Contributor

    Sorry, forgot that. I'm running an 800 CFM Quadrajet. Why block the return line?
     
    Last edited: Jun 26, 2020
  6. LARRY70GS

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

    See, here's the thing, detonation especially at sustained WOT, like on a track, is probably one of the most injurious events to an engine. Besides fuel of insufficient octane, high compression, or too much ignition timing, lean running is a major cause of detonation. The Stage 1 pump becomes inadequate at around 450 HP, but that isn't set in stone. I'm sure some guys are going fast with 3/8" stock line and a Stage1 pump, but I think they are the exception, not the rule. I was advised to go with a pusher pump as soon as I went to Aluminum heads, and I did. Did I need it? Maybe, maybe not, but just like adding some race gas at the track, improving your fuel system is money well spent as your engine power increases. When JW delivered my engine, he told me that he would like to see me add a fuel pressure gauge to my gauges inside the car. I did just that. I went further, I added an air/fuel gauge as well. For guys who want to experiment and see if they can get by with the bare minimum, I ask, what are you trying to prove? Phil Sedlon (70 gsconvt) learned the hard way, have a look at this thread,

    http://v8buick.com/index.php?threads/crap-my-blown-head-gasket-is-the-least-of-my-problems.182400/
     
  7. LARRY70GS

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

    Blocking the return line will get a little more pressure out of the pump. I used to do that. I used a ball valve inline with the rubber line so I could shut the return off when I wanted to.

    FuelReturnValve.jpg
     
  8. rkammer

    rkammer Gold Level Contributor

    Points all well taken, Larry. While I'm experimenting to see if I'm running "on the hairy edge", all my full throttle work will be while viewing the fuel pressure at the windshield and also will run 116 race gas to prevent detonation. If, after doing the upgrades I mentioned previously, the fuel pressure drops off under heavy load, I'll add the 1/2" lines and the RobbMC pump and be done with it. I don't race that often to want to spend the extra money if I don't have to and want to remain as stock appearing as possible. I'll be cautious.
     
  9. rkammer

    rkammer Gold Level Contributor

    I like that.
     
  10. BrunoD

    BrunoD Looking for Fast Eddie

    Well,all is well and good,but about 3 years ago I went .Larry was there also,to Atco,with10.2 compression,stock fuel pump,stock fuel line,original SI heads,the car went 11.70 and 112 MPH.Thats with a 462 CI and a mild cam,car idling at 700 RPM.Now its 470.bigger cam,idling at about 10.50 done more work to the heads and port matched the Eldee intake to the heads,still same fuel line and fuel pump.Is it faster?I will state a definite yes.What it will do in the quarter?Don't know,maybe it will fall on its face,maybe run in the mid to low elevens.We'll wait until I go to the track.Bruno
     
  11. 69hellcat

    69hellcat Well-Known Member

    69 Wildcat 464 Stage 2 10.80 124 mph with 1050 Holley Dominator. Stock sump and pick up with sock. Mallory 110 pusher pump at rear thru stock 3/8 fuel line to stock stage 1 fuel pump with return plugged. I have made passes with less than a quarter of a tank. No tank modifications. I dont know why but it has worked for many years now. Best 60 ft. 1.46
     
    Brett Slater likes this.
  12. johnriv67

    johnriv67 Well-Known Member

    While I don’t have the experience, I’d be wary of that. Go big or get towed home
     
  13. Rob Ross

    Rob Ross Well-Known Member

    Ray, here are my thoughts...the Stage 1 fuel pump was always marginal. If you run ethanol fuel it is even more marginal since you need more volume. Plus running the stock tank requires that you race with a full tank or mostly full since the fuel can run away from the pick up. I never had a 71-72 tank apart but I told there is some sort of baffle in there. You can block your return and it will up pressure but if you have a large seat in the carb the increased psi may overwhelm it. I run an Aeromotive Stealth electric pump in the tank. It has a sump that works well. It's not like a dedicated drag racing sump but hold pressure in my set up. My car is around 11.8x at 4050 lbs. You may be able to eek out more performance by getting rid of the factory style filter in the QJ housing, they are very restrictive. Had I realized that at the time, my car should have picked up. When it was stock appearing I ran 12.26 with a Stage 1 pump, no electric pump and it was nosing over. The Stage 1 pump is only about $30 on Amazon and it wouldn't surprise me if the quality varied a bit given who everything is optimized for cost these days.
     
    rallye, Brett Slater and kenny t like this.
  14. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    Their may be a slight hp gain when you compare tbe load of the mech pump arm on the cam. To tbe electrical load on alternator. Advantage on the electrical pump I think.
     
  15. rkammer

    rkammer Gold Level Contributor

  16. LARRY70GS

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

  17. GRNDNL

    GRNDNL Wannabe

    Mandys GS fuel system is all stock with the sock pulled off the pick-up and a Q-jet main jet stuck in the rubber return line by the pump as a restriction, the fuel pressure would jump around if I blocked it completely, without it it won't keep up at the top end. I had to try a few pumps to get one that would keep up, they are not all the same. Back in the 90's I put a larger pickup in the tank, electric pump and -8 line up to the stock fuel pump, car ran exactly the same, pulled it off when I raced a few f.a.s.t. races in the early 2000's, never bothered to change it back.

    I would not put any filter in front of a stock pump, they have a hard enough time pulling fuel already. I just run a stock filter with that little anti drain back valve removed, I haven't had any problems.

    All iron motor, 800 q-jet, pump gas with a splash of 110, 4050 lbs, best et 11.75 @ 113

    I like Robs setup, when/if I change anything it will be to a in tank pump like he's doing.
     
    joegsx, Johnny Angel and ranger like this.
  18. rkammer

    rkammer Gold Level Contributor

    Great feedback, thanks. So, you just don't run any filter, not even the paper filter, from the pump to the carb? And the stock filter you refer to is the sock in the tank? And what "little drain back valve" are you referring to?
     
  19. LARRY70GS

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

    It's a check valve that prevents fuel from draining back. It can increase restriction,

    https://quadrajetparts.com/long-paper-carburetor-fuel-filter-with-check-valve-p-82.html

    There are optional marine fuel filters you can use that are way less restrictive,

    https://quadrajetparts.com/short-marine-carburetor-fuel-filter-restriction-p-83.html

    https://quadrajetparts.com/short-mercury-marine-carburetor-fuel-filter-p-433.html
     
  20. GRNDNL

    GRNDNL Wannabe

    Running the stock filter in the Q-Jet like Larry is showing.

    I was told back in the 90's to remove the in tank sock, they are restrictive and can collapse, made sense to me.
     

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