I have a 71 GS-X clone with a 76' 455 block with 70 Stage 1 heads, 10:1 pistons, TA 413 cam, Edelbrock intake, 1 7/8 headers & full 3 in exhaust, munce 4 speed trans, 3:23 rear end and a rebuilt 800cfm quadrajet that I bought on e-bay that was a good deal & seems to run fine so far in the garage. My friend has a super clean 69 SS 396 Chevelle with a new crate motor 454 with 8.75:1 compression, very mild comp cam (compared to my TA 413) 2 inch headers & 3 inch exhaust, 4 speed also, 3:31 gears & Edelbrock intake with a Holley 770 Street Avenger on top. His motor is rated at 450hp & 500 lbs-ft of torque. He has gone thru many carb changes & when he jetted that 770 Street Avenger carb properly (front jet 72, rear jet 84) & stomped on the gas with me in the passenger seat that thing unleashed hell!!! It rips!!! We went to the track in his car (my body & paint is not finished yet) & he pulls mid to late 12s over 107 mph & that is with a not so good 60ft time & spinning T/A radials all the way down. So after that long story my question is this....Will a similarly jetted 770 Street avenger have the same effect on my car? Can anyone tell me what a good Stage 1 jetting is for my Q-jet? Holley vs Q-jet? Night & Day difference in performance? :3gears:
Hi. If you don't know about Qjets and know something about Holleys, the Holley will make more power. It also works vice versa. This thread kind shows that there really isn't a whole heck-of-alota people that know about Q-jets. The StreetAvenger 770 is a nice carb and is pretty good right out of the box. I never touched a Q-jet, but I would think that the driveabiliy/mileage would be better with it. This is what I suggest, borrow your buddies carb and see if you like it. If you do, get one! VG As Dan Akroyd said, "We mock, but we do not understand".
"We mock what we don't understand"....Yeah!....I believe I will take your advice & borrow that person's carb. His heads are off anyway. Wait!...I have an Idea...What was my idea? Oh right, get that carb & unleash some 4spd hell !!! :moonu: :3gears:
It is very likely that the Q jet, similarly metered will unleash the same kind of hell. It is not the carb that determines whether the engine works properly. It is whether the carb meters the correct amount of fuel that determines the performance. If the Q jet meters the same amount of fuel as the Holley the performance will be the same. The differences will be obvious when the Q jet is properly metered for the street, which is more difficult with the Holley. It will run equally well, and provide better economy. The difference is in the metering of the Holley, which is more difficult to access. If you understand the Q jet, the differences will disappear, the the expense of a new carb will not be necessary. Ray
Ray, Thanks for your reply. I don't understand the q-jet yet, That was the reason for the thread. I would love to keep the Q-jet & unleash hell, but I need to learn what makes that carb work. Is there anyone you know that has a similar combo car & what jets/metering rods they are using for a stage 1 application? :3gears:
Look at my combo below. John Osborne jetted my 800 CFM with 76 jets, 46B primary rods, and BG secondary rods My exhaust is 2 1/2" except for the hybrid X pipe(3" X 2 1/2") Do you know what jetting is in the carb now?
Edelbrock 1910 Q-jet 850 carb. I have a 70 GS stage 1 with a built 455 that runs 11.07 at 120 mph in the 1/4. It has a barry grant silver claw 1000 carb on a wildcat cool runner intake and a friend let me borrow his 850 Q-jet and the car run the same numbers and even had a better throttle response. It suprised me when a Q-jet is set up right how well it works. Thinking about getting one. :TU: Billy.
Billy & Larry, thanks for your responses. I have only driven it once until today & I found that I had a bad vacuum advance canister on my hei distributor. So I got a crane cams adjustible one & set the timing properly & took it out for a blast & wow!!! It is EVIL!! The carb is most likely fine the way it is, but I still want to learn more about it so I can tune it for optimum performance. I don't know what jets are in it now, but I will find out. Billy, what kind of engine combo do you have (compression, cam etc.) to run those numbers & Larry, I see your stats but is your compression 10.25 like stock? I'm trying to get a feel for what my car should run in the 1/4 with my combo. :3gears:
455 combo. 73, 455 block bored 30 over forged dished wiesco piston's notched and stock rod's. Cross drilled forged crank and all possible oil mod's done to the block with a TA timing cover and booster plate. Also have oil line running from the stock oil sending unit location back to the rear passenger side lifter galley and take oil pressure reading there. 69 430 stage 1 iron head's with lot's of port work done and TA 1.65 roller rocker's. Cam is a club lunati sp-4 with TA dual grooved cam bearing's and comp pro magnum lifter's. Motor rod's and head's have ARP stud's. TA deep sump oil pan and pick up. TA 2 inch tube headder's and 3 1/2 collector's with 3 inch exhaust out back. MSD 6AL box with HEI distrib and taylor 10mm wires autolite #24 plug's 45 gap. TH-400 tran's with shift kit and Coan 10 inch 3500 stall converter. 8.5 10 bolt posi 390 gear's. Wildcat cool runner intake and barry grant silver claw 1000 carb 82 jet's in front and 88"s in the back. 6.9 power valve in front and back is blocked off. 30cc accel pump in front and 50cc in the back. Compression is 10.5 to 1 and run's on 93 pump gas. 60 ft time is 1.51 and shift from first to second at 6000 rpm and also to third and goes threw the trap's at 6200. Car pull's both wheel's up even and goes straight. Wheel's are weld drag star's 15x10 with 28x10.50 hoosier quick time pro's and front is 3 1/2 weld drag star's with 27 inch tall skinnies. When i get my new digital camera i will post a lot of picture's of this car. It is a very nice car and i plan on being at the national's this year. I cut very good light's and i am ready to kick some butt..... :TU: Billy.
It has 10.2:1 forged pistons, but the deck height is stock, I believe. The compression could be anywhere from 9.6-9.8:1 I bought the car with the engine rebuilt already. Prior owner couldn't really give me any particulars. The Stage1 heads are untouched, and the car weighs 4110 with me in it.
If you want to "unleash hell", may I suggest digging deeper than the carb and replacing the motor with 454 BABY! :moonu:
454. Hell, I have beat so many 454's it's not even funny.... Chevell's,camaro's, And all those dime a dozen chevy's. HA HA HA HA :laugh: :laugh: :laugh: :laugh: Billy.
