More on the "small FE" idea....

[drdano]

A quadrajet!  Someone go beat that guy up too!     Small primaries and chunnel sized secondaries?!  Blasphemy! 

I live in Waco TX. I am 41 with crushed nerves in the lower 3 disc. Bring couple of MIA fighters, should be about even.

I'll bring my grandma, she's mean and loves quadrajets too.  Joking aside, I love quadrajets.  I'm not surprised you're approaching mid-teens for mileage with one.  I've seen close to 20mpg on a worn out 390 with one.

[chris401]

My thoughts on the low - mid torque also are in the design of the Holley carb to QJ intake adapter. I modified it to flip the other way so I could have a dual plane adapter. Look at how part throttle flows in a line to the center of the intake.

[chris401]

A quadrajet!  Someone go beat that guy up too!     Small primaries and chunnel sized secondaries?!  Blasphemy! 

I live in Waco TX. I am 41 with crushed nerves in the lower 3 disc. Bring couple of MIA fighters, should be about even.

I'll bring my grandma, she's mean and loves quadrajets too.  Joking aside, I love quadrajets.  I'm not surprised you're approaching mid-teens for mileage with one.  I've seen close to 20mpg on a worn out 390 with one.

We had similar experiences. My grandmas love was hard but genuine. If I had parents and grandparents that handed me things and looked the other way when I was wrong I probably would be confined to a cell or casket. I am glad they were tougher than I was.


NO DOUBT! If this intake and carb were set up on the 68-70 Galaxie 2v 390 power, torque and mileage would all be up.

[FElony]

My thoughts on the low - mid torque also are in the design of the Holley carb to QJ intake adapter. I modified it to flip the other way so I could have a dual plane adapter. Look at how part throttle flows in a line to the center of the intake.

Love the tough truck pic, but it seems to me that the secondaries are restricted with that spacer flipped over. Is there really much advantage over an Autolite 4V in this situation?

[chris401]

My thoughts on the low - mid torque also are in the design of the Holley carb to QJ intake adapter. I modified it to flip the other way so I could have a dual plane adapter. Look at how part throttle flows in a line to the center of the intake.

Love the tough truck pic, but it seems to me that the secondaries are restricted with that spacer flipped over. Is there really much advantage over an Autolite 4V in this situation?

Not sure. My 1.12 ran too lean on the right side and I have not put a kit in it yet. Maybe someone can print out the venture differences between the 66 Autolite 1.12 and the 76 Oldsmobile Quadra Jet pictured. I am running the 68 QJ.

[chris401]

AHH! Secondaries. Yes they are restricted. Latter on I am going to buy a couple more of these spacers and blend in the secondaries to match the carburetors.

[FElony]

Not sure. My 1.12 ran too lean on the right side and I have not put a kit in it yet. Maybe someone can print out the venture differences between the 66 Autolite 1.12 and the 76 Oldsmobile Quadra Jet pictured. I am running the 68 QJ.

Not an expert, but thinking about it, if it were mine, I'd try a single 1" open spacer between the manifold and the QJ. Allows for a little plenum above the four holes to equalize the flow from the carb without restricting the secondaries. ?

[drdano]

I hogged my 4-hole into a 2-hole.  The casting on this one wasn't quite up to snuff and the secondaries wouldn't actually open all the way before I modified it.  Still a restriction on the secondary side width-wise, but you can only go so far there due to the square bore intake underneath being narrower.  http://fepower.net/simplemachinesforum/index.php?topic=384.msg2976#msg2976

[chris401]

That lowest spacer cost me a couple hundred rpm off idle grunt. The air cleaner spacer giving the carb a straighter shot helped also.

[e philpott]

the trouble with Q-jets is on heavy vehicles , primary aren't big enough to feed a heavy load cruising and the big secondary is like a "trip hammer" trying control it is much harder than a square bore carb .... a light vehicle that can cruise on the primary they work better ..... another bad thing on Q-jets are that they only have one needle and seat assembly that has to feed 8 cylinders along with a small fuel bowl and a tiny float that has trouble controlling it

[drdano]

the trouble with Q-jets is on heavy vehicles , primary aren't big enough to feed a heavy load cruising and the big secondary is like a "trip hammer" trying control it is much harder than a square bore carb .... a light vehicle that can cruise on the primary they work better ..... another bad thing on Q-jets are that they only have one needle and seat assembly that has to feed 8 cylinders along with a small fuel bowl and a tiny float that has trouble controlling it

Common complaints against this carb.  Once you've set them up correctly, they are great.  I have the APT set on mine so at cruise down the highway, the primary is feeding my 428 just fine while the secondaries are closed getting decent mileage.  If I need to pass or climb a steep hill, the secondaries are cracked open and off we go.  I did have a fuel issue with mine, but it turned out to be the line size from the tank to the pump to the carb.  Once all that was addressed, it will run full bore til I float the valves with no fuel starvation using a carter mechanical pump.  I do have a windowed seat assembly in mine, but still using the stock plastic reservoir and told I can take that out if I need more volume should that arise.  The only thing I do not like is that you've got start doing modifications like drilling emulsion passages if you're going to run these on a motor that has low vacuum.  That I don't like at all.  But up til that point, they are a fine carb.  Second to fuel injection, it would be choice on a tow rig.

[chris401]

I plan on getting a tuning kit from Daytona Carbs. Does there needle design correct the fuel supply issue?

On that 42 mph hill in Salado's I-35 road construction I did have to back the secondaries off to 1/2 throttle due to predetonation.

[chris401]

Not sure. My 1.12 ran too lean on the right side and I have not put a kit in it yet. Maybe someone can print out the venture differences between the 66 Autolite 1.12 and the 76 Oldsmobile Quadra Jet pictured. I am running the 68 QJ.

Not an expert, but thinking about it, if it were mine, I'd try a single 1" open spacer between the manifold and the QJ. Allows for a little plenum above the four holes to equalize the flow from the carb without restricting the secondaries. ?

When I ran a Quadra Jet and a spread bore Motorcraft in my F-100 I used a Mr Gasket open adapter. You could hear and feel the secondaries open like they should. The spacer mods I want to test are opening up the secondaries similar to the Holley 3 barrel design, another would be blending them forward which would take advantage of Edelbrock's intake design.

I am no expert either. Just a broke guy trying to get the best out of a pile of old parts.

[machoneman]

"another bad thing on Q-jets are that they only have one needle and seat assembly that has to feed 8 cylinders along with a small fuel bowl and a tiny float that has trouble controlling it. "

Yes, exactly. I do remember that Stock class Chevy NHRA racers who were required to run a Q-Jets had fits not at launch but down track when the engine was starved for fuel near the finish line. Don't remember exactly how they overcame the fast emptying fuel bowl but it likely had to do with a massive increase in pressure.   

[nhsohc]

To take this one step further, just use a Thermoquad.  All the advantages of the QJ without the problems.  Mopar guys have been very successful with them in stock classes.  Used on 318 through 440 engines from the early '70s to the mid to late '80s.  Pretty simple once you learn what not to do.