Holley Sniper Question

Discussion in 'High Tech for Old Iron' started by rdirks, Sep 25, 2021.

  1. rdirks

    rdirks Well-Known Member

    I am building a 482 for the street. The expectation is 550-600 for both HP and Tq. I am trying to decide between rebuilding the quadrajet or going EFI. The Holley sniper line seems to be pretty popular but I’m going to have a bit more HP than their Quadrajet style model which is rated for 500HP and is the only one offered specifically for a spread bore manifold (Holley SPX in this case).

    They make models rated for 650HP (super sniper) and 800HP (XFlow) which only come in square bore but according to the Holley website, these seem to fit spreadbore manifolds with a recommended gasket kit.

    I have two questions:
    1. Is anyone running a square bore sniper on a spreadbore manifold?
    2. How does the height compare to a quadrajet? Hood clearance is an issue and I’m already 1.5” taller than stock with the SPX

    Thanks in advance. - Rich
    Last edited: Sep 25, 2021
  2. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Switch intakes and use a squarebore EFI.
  3. Sebambam

    Sebambam Well-Known Member

    I am not 100% sure if this answers your question but the SNIPER come with 8 holes for 2 different patterns. At least mine does ( Super Sniper) Just call teh Holley peops they will help you
    I have my sniper on a boosted setup ...it runs great. Much better than the Blowthrough carb.
    the height is pretty much the same as a Qjet.

    If you dont have the fuel delivey sorted out yet for EFI (58-60psi needed) i recommend a Surge tank feed by the stock mechanical FP and from the surge tank to the EFI. I have a Robb MC, but edelbrock has them too.

    Another tip , order from SUMMIT they have most of it on the shelves, Holley is out for another 12+ weeks!
    mbryson, rdirks and sean Buick 76 like this.
  4. LARRY70GS

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

    I have a spreadbore pattern SP1 intake. I run my Holley 1000DP and Q-jet on it with absolutely no problem at all. The spreadbore opening is actually preferred because you can run either carburetor on it. That is not true for the squarebore opening, the back throttle blades of a Q-jet will hit at the back of the opening. You have both bolt patterns for a reason. Just switch the carburetor studs to the right bolt pattern, and put the squarebore gasket on, and then the squarebore carburetor or EFI throttle body. I use an additional thin plate to square the opening out, but it isn't really necessary.


    It is thin, so it shouldn't be a big deal for hood clearance, but that is an issue with the earlier cars.
    rdirks likes this.
  5. rdirks

    rdirks Well-Known Member

    I agree this would be easiest if I didnt already have the spreadbore SPX and parts were easy to get -the one I got was the last one TA had for a while from what I understand.

    Are you saying to change manifolds beacause you know of some incompatibility?
  6. rdirks

    rdirks Well-Known Member

    Thank you - very helpful
    mbryson likes this.
  7. rdirks

    rdirks Well-Known Member

    Great info - thanks Larry
  8. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I stand corrected, listen to Larry. Your intake should work fine with a square bore efi.
  9. boe

    boe Well-Known Member

    No disagreements with Larry and Sean. I will add I'm going down a path with a machined down SPX and square bore Accufab 4150 style which combined has same height as quadrajet plus factory intake 400/430/455.

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