i own a 84 gs with a holley carb no clue what the cfm is but im leaning twords 600 , anyway ive tryed changing the main needles from 62 that it had when i bought it and tryed as far as 40 , so far 50 is ok but it has a dead spot when driving around 50, 60, 70 mph and as i eas off the gas to hold any speed it starts to wanna shot off and kick back in and shout off, so my question is anyone know of a good holley carb i can put on this car , ive gone thru 4 cats already and im going nutts lookin for the best fix. i would like to stick to holley since the car has the manafold for holley atm. would love to get better gas milage too , as for the exhaust . the headers are racing beat headersa then comes 2 inline cats universal one after another , cause im trying to keep emissions down aswell , but i think these cats are on there way out aswell . any help would be appreciated , thanks

oh and the muffler is a magnaflo

 

if it's the stock 12a, the holley RB sells for it is a 465cfm. they're ur best bet if u want to just replace it. mazdatrix may also sell them. u can also try the classifieds section on this site. the accelerator pump cam may be worn and need replacing if a very gradual movement of the throttle results in little to no squirt from the nozzles. i've been thru mine several time and can't seem to get the off idle/transition problem straightened out. as for better gas mileage, u'd be better off going back to the stock carb and intake. if u get some pix i can tell u if it's a RB carb or not, like where the cable hooks to it.