holley vs q-jet

[bulldog_m_c]

Carbs

It's hard get the best out of both My exsperience with the Q-Jet is it get a lot better fuel mileage but little performence. I have a 4 barrel holley on my 84 ss monte now it is good for performence but i can only get about 220 miles on 18 gal. If you want both performence and fuel mileage go with EFI from Edelbrock I have it on my 85 SS Monte and i Get 450 miles to tank and lots of performence.

 

[TBRtat2]

Lets make this simple.

Holley has been by far proven by dyno's and track's all over the world to be the best peformer (if you know how to use them), They are racing carbs, and should be used for such, they are very very touchy when it come to setting them, and if you run 1 you will want to adjust it everytime the weather changes, look at the guys at the race tracks, they are adjusting them inbetween every run. Basicly if you can keep it in tune, you will have the most power posible.

The edelbrock "style" (which is the same as the carte afb, they are both made by the same company, look at the top of the carbs, notice the W molded into the carb top) These are perfect for everyday drivers that get put on the strip from time to time. These carbs are eay to adjust, and I find that they really only need to be adjusted once, maybe twice a year(I like to set them for the winter, or summer, ie. a lil more or less fuel) most guys only set them when installing them and then they leave it.

as for the q-jet:
That depends on which 1 you are talking about. There are 2 dif setups for these, 1: stockers, 2: modid racers.

1: they are perfect for what they were used for, stock. They have lil to no peformance aps, but they are dependable (how many hollys, or edelbrocks, are running around with more then 200,000 miles on them)

2: now these are a lil different, these are built for mild peformance aps. slash street cars, they can be made to run dam good, but they will last a good long time, and are awsome for "out of the box" stock races. and are as easy to adjust, also if you have 1 of they guide books, you can turn some of the stock q-jets into the racing style q-jet like edelbrock sells, (Kinda like porting and polishing a set of stock heads) there are also a few companies they do they mod work (at least there used to be, havent checked in a while)



Now there is a question I have. Why does no one seem to have everheard of the prederter? (look in jegs) Which has "a self adjusting" cfm rating up to 930cfm, the cool thing is that if your engine doesent need it, it doesnt use it. Now these are a true racing carb. (not very good for a low stable idle, ie street use) And these are 1 of the few carbs that doesnt have the leaning out issue that most carbs have on a blower. 1 thing I have found on these, is they love LARGE displacement engins. Althoe they are not for any type of economy driving.

 

[olds307 and 403]

I love Qjets, very nice street carbs. They work great when matched to the application. I found that my holley reman 403 Qjet ran great on a vin y 5A 307 and on my 403. My 403 is constantly getting upgraded, just been changing the secondary hanger and rods richer with my performance mods. The stock 76 350 carb works great on my truck with the mild 350 Olds in it. Both my Qjet powered vehicles get at least in the 20-25 mpg range depending on how I drive it.I have never ran a Edelbrock/Carter AFB or AVS but here they are also crude on tuning for power AND economy. I have ran a Carter thermoquad, good carb. My only complaint is I could never get the choke to work properly on my superquad. I have the aftermarket 800 cfm model, supposed to be an excellent performance tune on these carbs. The factory thermoquads were super lean and need many internal passages enlarged to perform properly. Similar to later Qjets that way. i plan to use this carb if I ever get to the track, rebuilt and choke plates removed. The holley can be tuned for power and decent economy if you know what your doing. You lose economy/part throttle performance compared to to properly tuned Qjet. You will gain 10-15 hp up top comparing proper size holley to stock application Qjet setup in most cases. Of course swapping secondary metering rods and hangers will narrow the gap considerbly. I saw the comparsion of a 750 holley and a stock 73 400 qjet. Was 13 hp difference, 400 was upgraded with better heads, exhaust, cam and compression.

 

[drop the hammer]

well I thow in my vote for edlbrock. Holleys are a pain in the *ss and anyone who is running them knows it. I'll never use them again. If I had a real race engine I'd run a demon. I have had three 350's and have edlebrock performer intakes on them all with two running performer 650 crm's and on the buick I went a little different. I got the thunder series AVS 650 CFM offroad series. It has the springs set up for a truck bouncing all over a trail, so no matter how hard I launch or corner it never sputters. Tuned correctly out of the box. I pulled the shot leaking holley off, threw the edlebrock on and it ran better, got better milage, and I havent had to mess with it yet. Runs like a champ and easy to play with. Balls out performance I couldnt tell you, good performance with very little matience, 100%

 

[username]

I will have to agree that a carter/edelbrock is probably the best for every day driving. I can speak from personal experince I once had an old chevy truck I had put an edelbrock on. I used to work a swing shift well long story short I had been working 60+ hours a week was tired as can be.I went out one evening in the winter started my truck to warm up and went back inside and fell ASLEEP :shock: 7-8 hours later my roomate was getting up to leave for work came woke me up to ask me was I going somewhere?I had let that thing idle for at least 7 hours went outside revved it up a couple times no hestiation or black smoke.Definitely a goof proof carb!

 

[86Cutlass383SR]

Well, let me voice my experiences without reading others comments before I vote.

I've had a few Holley's and never had any luck with them. I firmly believe in the Q-Jets. Millions of them can't be bad.

I've also had 3 Carter AFB's. Bolted them on, set idle mixture and speed. And basically forgot about them. I voted for the Carter.

 

[chpbstrd1]

I own four g body vehicles. three of them have q jets, and one has a holley. The three with q jets are street cars and the one with the holley is a street/strip application. the main reason I have the holley on that car is because I run a single stage plate and I already had the square flange holley style plate. I gained more respect for q jets while running a dirt track car a few years back where the rules only allowed OEM carbs. I learned, and am still learning how to performance tune the q jet. I may in the future play around with a q jet on my 408 motor. If I can get it to run as good as my holley i may keep it and change plate set ups, however the current single plane race intakes favor the square flange base. Just my thoughts.

 

[85 Cutlass Brougham]

I own four g body vehicles. three of them have q jets, and one has a holley. The three with q jets are street cars and the one with the holley is a street/strip application. the main reason I have the holley on that car is because I run a single stage plate and I already had the square flange holley style plate. I gained more respect for q jets while running a dirt track car a few years back where the rules only allowed OEM carbs. I learned, and am still learning how to performance tune the q jet. I may in the future play around with a q jet on my 408 motor. If I can get it to run as good as my holley i may keep it and change plate set ups, however the current single plane race intakes favor the square flange base. Just my thoughts.

I will agree with you there. There really is no benefit to running a Quadrajet on a race car, except for class rules. The larger float bowl of a Holley makes it better suited to a car that spends a lot of it's time at WOT, as the Q-Jet has a very small float bowl by comparison and can suffer starvation if not fed by sufficient volume. Plus, the benefits of a spread bore carb are not realized on a race track as much as they are seen on the street. Gross volume of fuel and air is all that matters. However, on a street car it is very hard to beat a Quadrajet.

 

[79GP6.6L]

I voted for Holley because I don't seem to have the problems with them that others are complaining about. I run a 3310 with an electric choke conversion, and it works well for my combo. Although I will say the manual choke was pretty useless.

 

[gto78]

I have reasons for preferring both Holley and Q-jet, but overall I stick with Holley since I know how to tune it. My choice is the 4011 model Holley. It's the 650 spread bore, double pump, with the new style one piece body. It looks nice since they sell it with a polished aluminum finish, but that's not a good reason to get one.

I used to race every week and making jet changes in between rounds was very messy and dangerous with old school holley's. You had to remove the bowls and dump fuel all over the engine.... screw that. Then every few months the bowl gaskets leak...screw that too LOL. Then I got the new style 4011 Holley, and changing jets was just popping a few screws out, lifting the top off the carb, and not having to drain one drop of fuel. In fact I can swap both floats, needle and seats, all the jets, and readjust the floats in abot 10 min without one drop of fuel coming out of the carb onto the hot engine. The one piece body doesn't have any bowl gaskets at all, less chances of a leak happening. Also, the newer style 4011 came with the much more efficient Annular Discharge venturis which atomize fuel better.

As for q-jets I never figured out how to get them put together properly without bending a rod or ripping a gasket. I know they're great since the pretty much automatically vary the CFM to meet the engine needs.