I replaced the Edelbrock Performer carb on my 350 Malibu with a rebuilt QJ from Summit. Feels like it found another 50 hp at least. Talk about bang for the buck, this trick did it. Other mods in store for the old car. Next the 2:41 gears are coming out of the rear and 3:42's will replace them. That should make a difference, too. Will let you know what happens...........:2_thumbs_up_-_anima
So, what CFM did to go from and to what? I put an Edelbrock on my 455 and it feels like I lost a big chunk of power. Fuel mileage stayed about the same, about the only noticeable advantage was the choke on the Edelbrock works and the one on the Rochester was AWOL.
I just rebuilt the Q-jet on my daily driver '71 Olds 98 455, and wow! It is like new! Starts with the touch of the key and peels out! I'm so impressed with how great this wonderful car drives now. Charged up the A/C too! Ice cold! Life is good again! :2_thumbs_up_-_anima David
OK, that does it. Two of you having fun. I'm going to pull a couple of my quad's out of stock and build a good one and give it a shot on the car. I'm tired of the pent up power staying pent up. The Chevelle has the Rochestor on it and I love the sound of the secondaries opening. Oh sure, the fuel consumption is up a tad but I think it is worth every penny.
The Edelbrock was a 500 CFM and the QJ is a 750 CFM, which from all I have heard all my life is way too big for a 350. However, since GM put them on V6s, & 305s I decided to give one a try. Since the primaries are so small, I would think that fuel economy would be a little better with the QJ, as long as we keep our feet out of the secondaries (hard to do). I will probably kill my 15 MPG with the new rear gears, but since it will take less power to move the car, due to gearing, maybe it won't suffer much.
I have had good luck with E-Carbs when all you want is stock or something better than a 2 BBL. I agree that the hopped up QJ or a Holley is a much better choice. I went from an E-carb 600 to a Holley 750. Much better. I too am going to change the 2.56's in the Tempest to 3.23s. Should be night and day.!! Love to see some pictures!! Dave
I have no idea why so many people do not like the QJets and replace them with Edelbrocks and them puke Holleys? A good tuned QJet will stop the tail off any aftermarket carb, Car Craft did a test that proved its power making performance across the entire board. We had this discussing way back on this forum and I am glad you decided to take the advice and upgrade to stock over aftermarket. Its also great that you can see and feel the MAJOR increase in performance and came back to give us a heads up about it. Good on ya!
I love QJ's and am not a fan of Edlebrock. The only problem with QJ's is that some of them have problems and just won't stand a rebuild. If you have a fussy QJ and rebuild it and it still gives you problems....may as well junk it. But...get another QJ....they are simply a great carb! I have used the Edlebrock carb & intake packages on some built engines and they never got out of the hole like a QJ....never. If you can find a good old QJ guy, go to him and let him set yours up for peak performance. You will be amazed at what these old QJ guys can get out of these carbs.
As I mentioned before, the QJ seems way too large for a small block anything. To the best of my knowledge, the small QJ flows 750 CFM. I have always heard it was better to have a little too small carb than one too big. But, as I said, I have seen v6 Olds engines with QJs. My wifes' 89 Caddy Brougham has a QJ on the 307 Olds power plant. All I know is the thing works. Blows the theories all to Hell, but that's the way it is. Kinda like the Carter TQ, lots of carb for small engines, like the 318. I have stayed away from most Rochester carbs because they are so complex. I have always favored Carter and Holley because they are much simpler with less stuff to go wrong. I have always used Holleys with mechanical linkage...to me the vacuum secondary system is not all that great. I never had one that worked right if at all. My last Holley was on my Volare wagon with the 360. I had a 650 DP spreadbore on it and she would stroll. But, so far, this QJ has really impressed me. I started to buy a used one, but decided to go with a fresh pro rebuild from Summit. A little over $300, but worth it.
I have been rebuilding/tuning/driving/and racing with Q-Jets since the mid 1970's and as far as I'm concerned it's the best carb out there. I have used them on everything from small displacement V8's to turbocharged big blocks. It's extremely versatile and adjustable for just about any application that needs up to 800CFM airflow. My own tests and experience confirm what Car Craft discovered. The downside is that it's a bit complicated as compared to a Holley and for tuning, you need to have an assortment of jets and metering rods as well as knowledge of all the various adjustments available, modifications, and how to do them. Over the years, I compiled a chart of what jets/metering rods/hangars were in various OEM Q-Jets so it gives me a baseline when I build one from scratch for something.
