Buick Guys have known for years that if you put a larger carburetor on a Buick engine, it will go faster ON THE TRACK. On the street, a smaller carburetor might have better throttle response, street manners, and fuel economy. Having said that, calibration is very important. How many guys actually take the time to do that, or have it done? Most guys rely on someone else to calibrate the carburetor for them (including me), and then bolt it on and go. Years ago, one of the car magazines did a big block engine dyno shootout. I remember they used a 750 CFM Holley 4150 type carburetor on all the engines. They used aluminum heads and intakes. IIRC, the Buick made the most HP. Afterwards, they put a bigger carburetor on the Buick and made even more HP. The formula predicts the Buick will not need more CFM than any other engine of whatever size, but Buick guys know better.
Gary and the forum. Thought you guys would like to read what I found on the internet today. Great write-up but one big error I believe! Vet I never heard of this > Buick also launched a more powerful Skylark GSX S2 with a 7.5-liter V8 engine under the hood, which delivered a peak power output of 540 hp. Did I miss something on the forum??? 1970 Buick Skylark The 1970 Buick Skylark is known for its powerful engine, which make it an ideal option for those looking for performance and a dominating character. Buick also launched a more powerful Skylark GSX S2 with a 7.5-liter V8 engine under the hood, which delivered a peak power output of 540 hp. In addition to a powerful engine, the Skylark GSX S2 also boasts a number of mechanical updates to handle that extra power and offer improved dynamics. Despite all the performance upgrades, the '70 Skylark GSX S2 outshines most of its rivals with its prowess and reliability. It was because of these factors that the '70 Skylark GSX is renowned as a legendary street racing muscle car. 1970 Skylark Reliability Based On Owner Feedback One 1970 Skylark owner with a GS Stage 1 model provided feedback on Carsurvey.org. Acquired in 1982 with 114,000 miles, the owner last reported getting it up to 253,000 miles in 2002. Two faults cited include the head gaskets leaking along with the alternator and starter going out around 130,000 miles. Problems Owners Report: Head gaskets leaking, alternator and starter failure Highest Mileage Reported On Carsurvey: 253,000 miles
I run that 750 CFM Holley 4150 on my 70 Buick GS 455 and it performs very well, I have no complaints. VET
10% loss, maybe so. Next summer, depending on, if I have extra $$$, I'm not opposed to trying a 800 cfm Buick QJet. Finding a Non-Chinese brand is difficult. Reason why I went to a Holley is because I bought a QJet from Jet Performance and RIGHT out of the box it was bad. A real piece of S***. I will have to find an original core (if that's possible) and get one of the guys to clean it & rebuild & tune it up. I imagine, that will be a costly $$$$ affair, including shipping costs. In the meantime, it's the Holley. It's not a drag car, street only so ET's are not a big deal to me. (:>)
Well then, send me that POS Qjet and I can use it, I rebuilt my 800 with parts from Cliff Ruggles and his book, the QJet godfather. Original cores are $50 all day long and very easy to find. But if your happy with the Holley stick with it.
An 0240 will be around $500 tou your door The Jet carbs are a generic calibration....the edelbrock qjets were pretty nice I ran of the hot dog versions a 1910 model can remember for sure...but a Norm Dihle built unit replaced it.... There's alot wrong with that article btw....there was never a factory built and sold stage 2....there was a white GSX that was outfitted with the stage 2 goodies by Denny and his crew and whored out to a few magazines for review...which they blew it up
Robb Ross...Ken at Everyday...JW...Mark at quadrant power...all build and know Buick carbs...I've built more than a few myself...I do them a little different than some guys...but I've spent hours and hours at the track and driving around...pulling over and goin thru and making changes on the side of road and gas station parking lots making changes and trying again.....and tbh....leaving everything as Buick spec'd them....any changes you make are like splitting hairs
Our own Guy Parquette here on the board has the closest to factory assembled stage 2 there is as far as I'm aware....obviously Guy can fill in the details but his and the red Jones and Benisek car are the only 2 factory backed/supplied stage 2 cars....hard to remember exact details but all the info is here on the board
I guess I'm very curious, on this forum, if you're NOT running a Qjet on your Buick, I seem like I'm an outcast. That said, I'm curious to see if the 800 QJet will make that much performance difference over the Holley? But I hesitate to spend more money to find out and I'm NOT racing. If I were, and I could gain .02 or .03 on the ET it might be worth it???
Rob Ross likely has one ready to go for your car. Especially, since your build is similar to a lot of warmed over 455's here on the board or he could do a little tweaking to make it perfect. Nonetheless, he's only a private message away.
Brett, how can he tweak it if he can't get access to my car? I live in Virginia, 15 miles south of Washington DC. The fact he has QJets in his stock and maybe ready to go is a huge plus-up I didn't know about. So does Ross do this for a living? What info does he need from me to get the QJet tuned to optimal performance? Quick question, is the 800 cfm QJet a single or double pumper? I really appreciate you reaching out to me, thank you. Sorry for all the questions, theses QJets are new to me, never played with one. Vet
Qjet is one pump, it’s better than Holley because it gives both fuel economy and performance, Holley is performance only more or less. You’re not an outcast, those of us that know just know a good Qjet is the bomb.
Lots of the racers on here run Holley. I would say most. Larry switches back and forth. Holley for the track, and QJet for the street. Look at the Dyno results. Unless you are racing and trying to squeeze out every last hundredth of a second. I don't feel this is worth pursuing. If your intake is for a square bore, that's an issue too with the Qjet. Just sayin'
I have an AED 1000HO carburetor for the track. I run an 800 Q-jet on the street. The AED is consistently 1.5 tenths and 1.5 MPH faster than the 800 Q-jet. That's just a matter of air flow. The Buick engine shouldn't need anything bigger than a 750 CFM carb according to the formula, but the Buick engine doesn't know that. All the Chevy guys will tell you you are over carbureted. Track results don't lie. I much prefer the Q-jet on the street. It has better fuel economy. The AED is fun though, and the double pumper changes how the car feels. The AED feels like it opens up all at once.
That’s the beauty of the carter competition series thousand TQ, fuel economy of the Quadro jet, and the performance of a Holley.
Max, my intake is the original cast iron but has been ported. So, it's not for a square bore. But I don't think the port job is anything special, it was just for a little mid, just like the the Comp Cam, it a mild cam but stronger than the original Stage 1 cam. Vet
That's one of the nice things about a qjet....for most combos especially ones that's been done to death....it doesn't require any special in terms of tuning....it does a very efficient job of getting the air and fuel mixed....the only real adjust other than curb idle and mixture is air door opening rate which is beyond simple to adjust
