New air-gap manifold and custom/rebuilt q-jet. Sounds good but I still need to set the timing on the distributor and the carb is tuned already. Hope you like, nothing to fancy just a few revs and walk around...the Exhaust is true dual no x/h pipe and it has cherry bomb glasspacks(3 inch)
Rochester QUADRAJET, primay shaft play........
a very well know problem that makes this car very hard or impossible to tune.
see more at : http://www.pro-v8.com
More Quadrajet tuning, some things! Part one in this saga on Sept 13, 2010
The car has a slight stumble and surge at a light throttle cruise at about 55 to 60 MPH. By swapping out the .050 metering rods to .048 units, the stumble and driveability concerns are now gone. Going richer would mean worse fuel mileage one may think? No! Now that the mixture is right, LESS throttle opening is needed now, which means higher vacuum, and this way the metering rods will block off the correct amount of fuel, and in the proper timing and percentages, so the car runs much smoother. As stated many times, patience and reading up on, and understanding how these intricate carburetors work will help out very much! Enjoy!
1969 Chevy Nova Comp Cam Mutha Thumpr Cam Idle
This is my Street Strip Nova that I've owned since 1979 SBC ZZ4 Stage 3 kit: Comp Cam Mutha Thumper hydraulic roller cam, Comp Magnum push rods, Comp Ultra Pro Magnum roller rockers, Comp Beehive valve springs, Edelbrock Airgap RPM Intake manifold and Speed Demon 750 carb. Headman (3/4 length) Headers ( D-port Flange) 2.5" full length Exhaust with Pro Flow mufflers
'77 Chevy K20: Quadrajet Choke Pull Off and Fast Idle Cam Observations
1977 Chevy K20. 350 crate engine. Rochester Quadrajet 4MV carburetor with divorced choke.
Truck suffers from unexplained hesitation and bogging when in forward gears. Tends to rev just fine after a few minutes of mixed idling and high revving. Checking choke operations as well as a possible sticky fast idle cam as part of the process of elimination.
- Truck is allowed to idle/warm up until 2:25 mark, at which point the engine is revved to about 2,000 rpm, and can be heard bogging (a hissing sound can be heard). The fast idle cam is seen dropping. Fuel flow can be seen in the glass-cased fuel filter right before the carb as remaining steady.
- The engine is revved again about three more time up until 3:00 minute mark. The engine revs slightly higher, but the hissing and bogging can still be heard.
- Engine is revved again at the 3:35 mark, slightly past the 3,000 rpm mark. Hesitation and hissing still evident, but less so than before.
- Engine revved at the 4:25 mark to about 4,000 rpm. No hesitation or hissing heard.
- Transmission is slowly shift through every gear starting at 4:55 mark. Shifted back into Park at 5:05 mark.
- Engine revved again at 5:10 and 5:17 marks to 4,000 rpm. No hesitation or hissing is heard.
To read up on the discussion, please visit the following thread: http://www.hotrodders.com/forum/1977-chevy-k20-engine-suffers-hesitation-power-loss-when-drive-213757.html
More Quadrajet tuning, some things! Part two in this Saga Sept 13, 2010
With the camera sitting on the oil filler cap a few more things to show how a metering rod system works on a carburetor. The car has a slight stumble and surge at a light throttle cruise at about 55 to 60 MPH. By swapping out the .050 metering rods to .048 units, the stumble and driveability concerns are now gone. Going richer would mean worse fuel mileage one may think? No! Now that the mixture is right, LESS throttle opening is needed now, which means higher vacuum, and this way the metering rods will block off the correct amount of fuel, and in the proper timing and percentages, so the car runs much smoother. As stated many times, patience and reading up on, and understanding how these intricate carburetors work will help out very much! Enjoy!
Monte Carlo SS 305 H.O. engine install part 4 - it's done!
Finally got the engine finished up and running. All I have left is to replace the fuel tank and it should be a driver. Had some problems getting it to run with fuel pump sourced fuel. Ended up having to take the top of the Q-jet carb and loosening up the float (it sat unused for 14 years!). Now all is well.
Nasty chevy 305 400hp
400hp 305 ported heads custom camshaft 850hp holley dp 9.5:1 compression, just spare parts i had laying around. file fit moly rings stock crank and stock pistons with 80,000 miles just new bearings. I built this engine for the burnout competition for car craft, after car craft in goes the big block. just hope i finish painting it....
How to de-bog your Quadrajet part 2
The Rochester Quadrajet has gotten a bad rap over the years, but it's actually an excellent carburetor once you understand how they work.
Often referred to as "Quadrabog" or "Quadrajunk", many of the issues these units suffer stem from neglect, or "modifications" that do more harm than good.
Being a spreadbore, air-valve secondary design, the Quadrajet is capable of flowing 750 or 800 cfm of airflow, eliminating the need to buy different carburetors when your set-up changes. In addition, the small primaries make for great drivability and fuel economy.
In this clip, I'll discuss theory of operation on the secondary side, since that's where most problems arise. So, leave your preconceived notions at the door and let's see what makes these carburetors tick.