General Category > Quadrajet Carb Talk and Tips
Remanufactured Carburetors
Cliff Ruggles:
Lars obtained one and dissected it. Considering the time spent and what was needed to get it working OK one could start with a clean virgin core and build two or three of them with the same effort.
I'd note here that there are PLENTY of 1972-1978 Chevy divorced choke Q-jets still readily available and many have never even been apart. It was very common in that period to yank them off of engines before they reached their first birthday and install an aftermarket aluminum intake and shiny new carburetor. The factory was hit HARD with tightening emission standards and those carburetors were super lean and difficult to make work correctly, not to mention the engine they were sitting on had LOW compression, tiny retarded event camshafts in them, and other emission control devices to choke those engines down pretty hard.
Edelbrock in particular targeted that market pretty hard and sold millions of carbs/intakes. The advertising was so good that folks jumped all over that deal with just about every 350 SBC engine that left Detroit in that period. With all the promises of improved performance, fuel economy, etc, etc, they talked a LOT of folks into going that direction.
Lucky for me I grew up a dirt poor farm boy and couldn't afford any of it, so I spend my time working with the factory parts instead. When I did dabble with aftermarket carbs and intakes I was ALWAYS very disappointed in the end results. About all I saw was INCREASED fuel consumption for "normal" driving, worse ET and MPH at the track, and some "cobbling" involved with making those parts fit. Talking about it decades later I can say for sure the ONLY statement they made to get folks to buy those parts was that it took some weight off the front of the vehicle.
Back then virtually NO ONE tested anything, they just removed factory carbs, intakes and distributors, bolted on aftermarket stuff, put the stickers in their windows, jacked their cars WAY up in the rear, installed loud as hell glass packs and cruised the streets at night. If they could do a decent burnout leaving the High School parking lot after a ball game the parts made the grade.
I was already drag racing my car and had it well dialed in. Every single time without exception I removed a very well dialed in factory part with something from Edelbrock, Holley, Mallory, Crane, etc my car slowed down at the track. The funny part was that many of those parts I installed "felt" stronger on the street, especially the big intake manifolds and larger camshafts. I lost count of how many times I'd install a part and street test it leaving a BIG grin on my face and fully expecting to run a full second quicker at the track the next outing, then get my time slip after the first run with the new part and NEVER went quicker.
What I was experiencing with many of these parts was a "shift" in power, not making more of it. Big intakes and camshafts shift power to the upper mid-range and top end often killing off low end and average power. Without other changes like gearing and looser converters the vehicle will run worse more times than not.
Anyhow, back on track and I'll say here that unless one of those Chinesium pieces of bovine excrement fall in my lap it's unlikely I'll ever see the inside of one or waste my time messing with them for pretty much the same reason I avoid anything commercially "remanufactured" like the plague......FWIW.......Cliff
Brian B.:
X 2 regarding the cavalcade of performance parts from the late 70s and 80s. I didn't race back then but my pocketbook kept me from getting impacted too much.
I did however spend money on an aluminum intake that didn't seem to contribute much which I tossed.
Best thing I did do was keep my Quadrajet and install some good tri-y headers from H-O Racing.
Cliff Ruggles:
A few years back we had a very well prepared Pontiac 428 on the dyno (440cid). It was topped with aftermarket aluminum heads, custom ground 236/242 @ .050" hydraulic roller camshaft, 10.6 to 1 compression. I used very strong internals which included Ross pistons and Oliver rods, zero decked and .039" quench so this was a very well prepared street engine.
We started pulls with my own factory iron intake and Q-jet. We were nicely rewarded with 497hp @ 5800rpm's and 540ft lbs torque at 4200rpm's making over 500 ft lbs across most of the loaded RPM range.
The dyno shop, who also specializes in Pontiac engines had a brand new Edelbrock RPM intake in the dyno room and asked me to install it. The idea was to "see how much power the engine will really make". Game on! So while the engine was cooling down I swapped the iron intake for the RPM. The very next pull, to everyone's surprise was 491hp!
Yes, not a typo, the engine LOST power with the bigger intake. With that in mind think about how many folks replace factory intakes with larger intakes like the RPM and RPM "air gap" on much smaller engines with less compression, head flow and smaller camshafts and think they are now making more power.........FWIW.......Cliff
73ss:
I wonder where the chinese got the molds to cast them. Reverse engineer 3-d scan maybe? Who knows.
Cliff Ruggles:
Webber was making them for Edelbrock or so the rumor goes. It was reported that the molds were destroyed when they discontinued the Q-jet lineup.
We don't even know what they are being cast from, or if it will hold up to currently available fuel. This new fuel can be really hard on some materials including certain metals......
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