5.0_stang

i have an 84 stang and it has a 600 cfm carb, when i punch it from idle it stutters a little then picks up and hauls ***. is it that it is over carb'd? what size should go on for stock?

mdvaldosta

The carb size is right, have you tried adjusted it

roundman

sounds like you need a little bigger squirt out of the accelerator pump when you floor it. some carbs have two holes in the linkage for the pump, see if you can put the link in the second hole to increase the volume of the squirt. if this don't do it, you can get bigger nozzles for the accelerator pump squirters or increase the size of the pump diaphragm too or both if necessary to get the proper volume when you punch it. also check to make sure the float level is set correctly so the fuel level in the bowl is just a tad below the holes in the venturi for quicker throttle response. the 600 cfm size if about right, no more than 650 cfm unless you have lots of mods.

vfast

roundy if he put bigger squirters all he's doing is covering up the problem......I think first he needs a new power valve one maybe for less vacuum..then needs to buy a sec spring kit...and is this this even jetted right? as for going bigger used a stub stack this bring about 25-30 more cfm or just mill the air horn? what air filter are you useing?..also you can tailor the throttle by buying new plastic cams for the holley....buy a how to hotrod a holey you'll learn a ton from it

90LX50

Vfast, i think you hit the nail on the head. My friends camaro would do that when he'd blown a power valve in his Holley.

You made some good points as well, this bears further investigation......