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I need a new carb for my Camaro. It's a built 350 with Vortec Heads and a LT4 Hot Cam. The motor should be around 400hp. Should I go with a QJET or a Holley? My dad said both work well and its my choice. Its a 5 speed and its a weekend fun car. I want good throttle response and decent gas mileage. My dad is a pro at tuning Holleys and ok at quadrajets. Any recommendations are useful. And if Holley, which one?








I don't know if it matters, but here are the cam specs LT4 Hot Cam Specs
 

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I need a new carb for my Camaro. It's a built 350 with Vortec Heads and a LT4 Hot Cam. The motor should be around 400hp. Should I go with a QJET or a Holley? My dad said both work well and its my choice. Its a 5 speed and its a weekend fun car. I want good throttle response and decent gas mileage. My dad is a pro at tuning Holleys and ok at quadrajets. Any recommendations are useful. And if Holley, which one?








I don't know if it matters, but here are the cam specs LT4 Hot Cam Specs
This would like a 750 cfm carb, it is kind of take your pick but I'd lean toward the Holley as the Qjets are either rebuilds or New Old Stock (NOS). Edlebrock makes the old Carter AFB and AVS available new and Barry Grant's new Demon is a variation on that same theme. Summit makes the old Ford/Holley in a 750 it uses mostly Holley internals stuffed into a different body with annualr boost venturis which help mileage in these no metering rod carbs.

Bogie
 

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This would like a 750 cfm carb, it is kind of take your pick but I'd lean toward the Holley as the Qjets are either rebuilds or New Old Stock (NOS). Edlebrock makes the old Carter AFB and AVS available new and Barry Grant's new Demon is a variation on that same theme. Summit makes the old Ford/Holley in a 750 it uses mostly Holley internals stuffed into a different body with annualr boost venturis which help mileage in these no metering rod carbs.

Bogie
X2

The Qjet, if it was still available as a new aftermarket piece would be a great carb, but there are just too many clunks being rebuild - kinda.

Are you aware that if you have a Qjet intake, a Holley (or Edelbrock) is NOT a simple bolt on replacement with any adapter not being a great idea for performance
 

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If you want mileage get the Q-jet. If you want to step up the power later I would get a 750 double pumper in Holley or equivalent
 

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I have been told a q-jet is a good carb provided it's rebuilt and tuned properly. Problem is I have never seen one that meets both criteria.

I vote for getting a carb that's made in the 21st century so that rules out a q-jet. Your experiences may be different from mine. :cool:
 

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I would look at the Quick Fuel carbs, they are very tunable, all metering orifices are replaceable with screw in jets. Very useful for tuning.
 

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I put a Quick Fuel Slayer 750 on my 351C Mach 1 last year and I was very impressed. The best part is you can get a Brand New Slayer 750 CFM for $299 - $315 which is very reasonable.

Great Bang for the Buck :thumbup:

 

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There are several carburetors to choose from. Look at a Quick Fuel 750 with mechanical secondary. Give them a call for which series to choose. You also have the Holley 750 https://www.holley.com/products/fuel_systems/carburetors/ultra_xp/gas_ultra_xp/parts/0-80803RDX. Then you have AED's 750 Ho 750 http://www.summitracing.com/parts/aed-750ho-rd/overview/ or http://www.summitracing.com/parts/aed-750hom-rd/overview/. It is AED's version of the Holley XP. They modify it with custom jets, air bleeds, and power valves. It has a lot of extras for the price.
 

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I own both holley and quick fuel brand carbs and if your going to get a new holley style carb I recommend the quick fuel as you can adjust and tune everything on them and for the same price compared to a holley brand equivalent it would cost quite a bit more just to make a holley brand carb adjustable like the quick fuel.

The 750 vacuum secondary is just a little over $300 depending on where you buy it from and they are made a little more durable compared to holley brand.
 

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I absolutely love a spread bore Q jet. That being said if they made new ones today that is the carburetor I would use on all of my street machines. The problem is like has been said. They are getting old and it is hard to find a real good one that hasn't been "Backyard Rebuilt" so many times they are plum wore out.

What I like about the Q jet and other spread bore carburetors is the small primaries and oil barrel sized secondaries. It makes good fuel mileage around town if you stay out of the skinny pedal. When you get into the secondaries it gives you nice seat of the pants boost. A small primary for your low end. You don't need 750 cfm at low rpm. When the engine starts coming into the cam you give it all it wants and the performance is impressive.
 

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I need a new carb for my Camaro. It's a built 350 with Vortec Heads and a LT4 Hot Cam. The motor should be around 400hp. Should I go with a QJET or a Holley? My dad said both work well and its my choice. Its a 5 speed and its a weekend fun car. I want good throttle response and decent gas mileage. My dad is a pro at tuning Holleys and ok at quadrajets. Any recommendations are useful. And if Holley, which one?






I don't know if it matters, but here are the cam specs LT4 Hot Cam Specs

If you are looking for performance then go with the holley.If you want mileage go with the QJ.
 

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sea blue agrees with my original post

I'm thinking about getting a mechanical secondary. I think it would work better with a stick.
mechanical secondary carbs dont know if the car is a stick or auto? If you want mechanical secondaries then buy that! I only use double pumpers,,,and not little toys
 

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TAKE A KID TO A CAR SHOW
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Is 750 CFM too much? I don't want stinky exhaust at an idle..
Q jets were all 750s except for very few that were a little bigger!!! On a small engine the secondarys on a Q jet would not get the demand at full throttle to open all the way so they could install them on big blocks or small blocks but the Q jet was never a performance carb it was installed for economy and smooth driveability off the small primarys the secondarys used for passing and short bursts of acceleration ( NOT FOR full throttle 1/4 mile blasts) Like the Holley or old (now obsolete) Carters ( Edelbrock is not a Carter LOL)! Rochesters Square bores and Q jets are obsolete for a reason They were outperformed by all other designs and demand fell to nothing except as replacements for old stock autos, and restored vehicles!! The basic 750 cfm QJet casting is used from 231 CID to over 400 CID The same QJET can flow 800 CFM on the big 454!!

Jester (Chris)
 

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Right now I'm actually leaning toward a quick fuel carb.They look very tunable for the price! Anybody have experience with them?
Quick fuel is a pretty good carb (A copy cat Holley) The "pro form" copy cat is a little better, But both much cheaper and of less quality! They tune exactly like a comparable Holley, Out of the many I installed I was noticing that the spring on the front throttle on the quick fuels would wrap (or overlap on the pump cam and cause a bog, Some I sat on new intakes and they rocked I straight edged the intakes and they were true, so I needed thicker gaskets to compensate for the carb bases! They still need internal tuning , Power valve, jetting etc, to get max power , If you think just bolt it on and fool with external air bleeds and screws are tuneing your wasting your time and fooling yourself into thinking its running fine and a great carb because you still need to tune for elevation, temp, vacuum etc, etc, Its the same as a Holley or any of the Holley copy cats, they all have the same tunability depending what comparable models you order there are none simpler then the other!!!

I still prefer the Holleys They are just of a much better quality , and better machining ETC, Like the difference between an ARP bolt and one out of a hardware store bin!! They do the same thing but ones cheaper:thumbup:
When you handle and rebuild hundreds of carbs over the years like some of us on here do and track tune Disassembling the same carb over and over and dino tune you see the little things most people miss like the dexterity of the parts and how much abuse and handling they can stand up to!! If you just bolt them on and drive and do not tear into them much (like re jetting every time your at the track and between runs and changing air bleeds ETC) then get the cheaper copy cats ! or an Edelbrock THROW AWAY LOL:mwink: (GOOD paper wghts):mwink: You will not need the good quality of a Holley!!





Jester (Chris)
 
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