I have a 67 Chrysler 300 with a pretty much "stock" 440 hi po motor in it (TNT,Magnum or whatever you want to call it). Earlier this month I switched from a dual quad set up (that was problematic) to a single Edelbrock Thunder AVS on an Eddy Performer dual plane intake. The dual quad set up had an Eddy Performer AFB primary carb and an original Carter AFB secondary carb.

The switch for the most part was a BIG improvement by there are several annoying issues I did not have before.

GOOD: Much better (TOO good) throttle response
Plenty of power throughout the usual street driving range, from mild acceleration to full throttle blasts. The car feels much more responsive and feels like a 440 TNT should.

BAD: My fuel economy has gone from bad to WORSE. I was getting 11 to 13 mpg for the most part...I'm down to 9.5 mpg and this is with pretty conservative driving.
The throttle response is like an ON/OFF switch. Hit the throttle and if you are not careful the car will JUMP! Same thing if you try to move the throttle by hand in the engine compartment. A slight movement yielda a HUGE change in RPM.
The choke is probably set too rich...she starts OK but then kinda stumbles unless I stick my finger between the choke and the air horn to let a bit more air in..Then she smooths out nicely.

Overall I am happy with the exception of the mileage which is frankly unacceptable for a street driven car. I have the jetting charts for both the Eddy Performer AFB and the Eddy Thunder AVS and the Thunder is jetted 1 stage rich as a starting point. So I can try changing the jetting on the primary side to one very similar to the Eddy Performer.


ANYONE's IMpressions or suggestions??