Monte Running Rich

[79MaliCrazz]

I found out i have a 600cfm Holley on my 350sbc motor i read somewhere that if i have a carb to small it will run rich due to it trying to pump enough gas to make it run so they said for anything bigger then a 305v8 you should run a 650cfm carb minimum but i know that due to temp changes you have to adjust but my fuel pressure gauge is reading about 12lbs and rpm is at about 1100 sometimes 1250 i know thats high and needs to be adjusted but the car is sitting right now due to winter times but my question is can i adjust it to make it not run rich or should i just buy an Elderbrock 650 or higher carb the car is not being raced but ill like to have the power to get up and go when i want but it will be used more for cruising.Any advise would be great i dont know to much but im sure learning.

 

[Peter]

the size of the carb doesn't determine rich or lean. you definetly do not need a bigger carb on a 305, a 550 or 600 would be plenty of fuel for your engine. im not familar with holleys although they have a reputation of not being street use friendly, you just need to read the manuel about fuel mixture and how to properly adjust it but the size of your carb is fine

 

[85ss808]

You should check the Holley website- I'm pretty sure they have an interactive carb selector that will help you out but I'm pretty sure that 600cfm is not too small- if anything you should be able to get better throttle response at a small cost of top end power (assuming it can be tuned correctly). As for the fuel pressure- if the gauge is actually reading correctly, 12 lbs of fuel pressure is way too high for a carb- you should be looking for somewhere around 6-7 psi.

 

[carpenter383]

You should check the Holley website- I'm pretty sure they have an interactive carb selector that will help you out but I'm pretty sure that 600cfm is not too small- if anything you should be able to get better throttle response at a small cost of top end power (assuming it can be tuned correctly). As for the fuel pressure- if the gauge is actually reading correctly, 12 lbs of fuel pressure is way too high for a carb- you should be looking for somewhere around 6-7 psi.

X2 12 psi is way too much, 5 should do it

 

[79MaliCrazz]

thanks guys ill wait till it warms up some so i can get it tuned its to cold and 12lbs is to much ill see if dropping it to about 5 or 7 will do it but is that good enough if my motor has some mods.

 

[carpenter383]

thanks guys ill wait till it warms up some so i can get it tuned its to cold and 12lbs is to much ill see if dropping it to about 5 or 7 will do it but is that good enough if my motor has some mods.

5 psi is plenty even if you do some mods, it's the volume of fuel and the pump's abillity to maintain pressure that matters most.
With carbs you don't wan't high pressure or the float won't have enough pressure on the needle to hold the fuel back. This problem is magnified if you install a larger needle and seat which is a common carb mod, So keep that in mind.

 

[79MaliCrazz]

thanks guys ill wait till it warms up some so i can get it tuned its to cold and 12lbs is to much ill see if dropping it to about 5 or 7 will do it but is that good enough if my motor has some mods.

5 psi is plenty even if you do some mods, it's the volume of fuel and the pump's abillity to maintain pressure that matters most.
With carbs you don't wan't high pressure or the float won't have enough pressure on the needle to hold the fuel back. This problem is magnified if you install a larger needle and seat which is a common carb mod, So keep that in mind.

Thanks for the info.

 

[79MaliCrazz]

Sorry guys another quick question i was told also that it might have to big of a jet so its dumping fuel and the psi is at 9lbs and also you can smell the gas through the exhaust real bad if you stand next to it for a few minutes you will smell like gas but some think something is wrong with the carb but no one knows it hasnt been checked yet due to it still to cold to work on it outside.

 

[79MaliCrazz]

well found out one problem i have i didn't notice until my brother in law checked it out my car doesn't have a fuel regulator so thats one big issue so i ordered one and now i waiting to see if that stops the fuel problem.