i have a 1989 RS and someone did an engine swap with a 1985 h.o. 305.my car is not set up for an electronic carburetor so i need to put a manual carb on it.i want to buy a new holley carb and want it to be close or a little more than stock cfm but can not make mind up of what to get...i need a push please.

 

this is just me but i would put a 500 on a 305

 

I Just Rebuilt My 305 And My Head And Block Man ( An Avid Rod Builder ) Believed Firmly That A 600cfm Vacuum Secondary Would Work The Best For My Setup. It Is A Quite A Bit More Than Stock But, The 600cfm Should Work Fine For Your Application As Well. Just An Opinion Tho.

 

i would agree with SSS. i would go for an edelbrock carb for that application because they are cheap, but give you good performance also. if you plan on getting some other performance upgrades for it, i would go with a 600cfm. if you are keeping it stock, get a 500cfm, it will be better on gas then the 600, and you will have a little better throttle response.

 

well as a small piece of advice, if you are looking for price, holley is the way to go, they are cheaper at the smaller cfm, however are a huge pain in the *** to tune, for tunability i would go edelbrock. its better to go higher than stock, stock carb didnt flow nearly enough. 500 is good for streetability, 600 if you want upgrades as was stated. id go with the 500 and save up for a better motor myself. 305 just doesnt make power for cheap.

 

a 650 cfm would be more than enough for a 305, me personaly, im putting a 600 cfm holley on my 305