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  1. #1
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    What Carb to use

    Ok so the Vette is your bog standard L48 smog motor, I am getting rid of the smog pump, fitting a true dual exhaust with headers and will be removing the cat and will be getting the ignition sorted.

    The inlet is getting replaced by a dual plane performer unit so should I stick with the edelbrock carb or fit the Holley 600 I have in the shed, both need rebuilding.

    I have played with holleys before but never an edelbrock, I have rebuild kits for both and both will fit the inlet as I have a special adapter to fit square bore to spread bore.

    What are the pro's and con's of either?

  2. #2
    Carburetion 'sucks' !
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    I know some people love Edlebrock carbs - and bolt on without issues - personally I don't like them. They are Edlelbrocks version of the Carter AFB which was a performance staple on a number of muscle cars back in the late 60's. It wasn't perfect back then - there were issues (can't recall what they were) Edelbrock supposedly fixed them - but I hear they have other different issues now (again only hearsay so don't know what)
    There are Holleys and there are Holleys. The first category includes the sort of carb you buy second hand and is usually crap, knackered out and has fixed secondaries. The other Holleys are off the shelf new ones (and generally a 600 cfm) vac secondary that will bolt-on, fire up on most engines and need very little fine tuning, perhaps just a jet size or two or squirter tune. Very easy to tune 'old school', little to go wrong on a lo-po stock engine.
    Last edited by roscobbc; 21-04-18 at 11:20 PM.

  3. #3
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    Remember...my opinion is worth what it costs you...

    imnsho. i would look for a spreadbore Holley. been too long, so i dont remember LIST numbers and such, but its the best of both worlds; spreadbore bottom with 4160 [or 65 or 75...] top. Like Mr Rossco says, there are Holleys and there are holleys...actually, theres a whole nuther bunch of holleys on top of those [the OE units] Dont remember if your car has a third pedal, but just remember to NOT put a mechanical secondary unit on a slishbox.
    The unit Mr rossco is describing is [I imagine] the 1850 ; single line, 600 and vac sec. That is, as he says, a very generic, one size fits all unit, and will 'work' on most anything. Its larger cousin is the 3310 ; we usta call them 'seveneightydoollines' [one word] even tho the later ones are rated at 715 i believe. Again, a basic, universal carb that works ok in most street applications, but designed for larger engines than yours.
    Mr Rossco is correct that an 1850 with adapter will bolt on and fire right up, abnd do 90% of whatever you want. The only consideration[s] are height with the adapter ; Corvettes havent much hood clearance , and running a manual choke. [I think Holley offers an electric choke kit i just remembered.] Fairly easy and inexpensive solution.

    BUT... you know me...easy and cheap is never an option. If i couldnt find a suitable spreadbore Holley, i would seriously consider a Q jet. look to someone like Sean murphy induction or similar and buy a nicely built rochester for your application. Ive known several folk who have used his product with good success, and I put one on a GTO a few years ago, and it worked well, hooked up correctly and everything fit just like factory.

    Im not too big on the Edelbrock version of the AFB myself either; never owned one and know several people who swear by em, but they just dont lift my kilt.
    ymmv

  4. #4
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    I'm also a Holley fan. Had more flat spot trouble with Edelbrocks than I have ever had with Holleys. I'm also of the 3310 generation though. People bitch and moan about leaky Holleys but I've never had that trouble. It's usually down to spending no time nor money on them.

  5. #5
    Carburetion 'sucks' !
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    Probably should have mentioned a 'third' type of Holley ~ the 'generic' version by after-market names like ProForm etc - the one that share basic architecture with the Holleys, have interchangeable parts and usually come with with all the trick parts like replaceable secondary jets, idle bleed jets and '4 corner' idle adjustment. Again not really required for a 'cookin' lo-po L48 - or even mildly modded. As our Transatlantic sage Malamute will allude to - "don't you be goin' an' gettin' one of them there Holleys with the mechanical do-hicky secondaries"
    Last edited by roscobbc; 22-04-18 at 12:33 PM.

  6. #6
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    DUH...just remembered, you said you were using an aftermarket intake...so a square bore carb probably wont need an adapter, unless its one of those old SP2P Edelbrocks or the like. Still, if the intake is a/m , check for height - Corvettes dont leave you a lot of room. [and i STILL like spreadbores personally, regardless of manifold. ]

  7. #7
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    I found with the Edelbrock carbs that they do suffer from a flat spot just off idle, although with your car being manual it may not suffer from it
    The float bowls go dry if left sitting for a while, can be a pain with a mechanical pump
    They suffer from fuel percolation too, something to do with the material they are made from (can be a pain if sitting in stop/start slow moving traffic, although with a manual it may not notice as much)
    Didn't have any of those probs with a Holley

    On the plus side changing jets and general tuning is really easy and manage 23mpg'ish out of one compared to 18 with a Holley

    But think it's swings and roundabouts with the 2 though and just depends on what you feel most comfortable with

    Just wondering is it worth sticking with the carb you already have on the engine,(kinnda looks like a Rochester) thinking it'll already be tuned and all the plumbings in place

    Engine looks cool with the new valve covers on and in black too

  8. #8
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    Captain, you are correct it is a Quadrajet not an edelbrock, my mind wasn't thinking, the inlet manifold is an edelbrock dual plane spread bore, the existing carb is the quadrajet but I do have a 600 holley with vacuum secondaries that is in generally good condition just needs the gaskets doing as it has sat for years in the garage. The Quadrajet needs gaskets as well plus a sonic clean.

    The original carb plus the air pump and the cast inlet manifold have loads of vacuum pipes which I will have to work out which to blank off and which to use for the vacuum advance. The Holley is just billy basic.

    MJ it's a 4 speed manual.

    So does this change opinions?

  9. #9
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    Only change Mr Stilltrying is that you could use a mechanical secondary unit since the car has a proper gearbox.

    Looks like it has a double row timing chain in one of the photos - thats nice and means someones been in it before; check clearances etc before reassembling, and while its apart, i would suggest rings - n - bearings...but you know me.

  10. #10
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    Would be tempted to stick with the Quadrajet. Not sure if there would be a lot to gain by going with the Holley, and may help with bonnet clearance

    It may need a little tweaking though after swapping out that smog cam while the engines on the stand

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