my94pony

my 85 5.0 came with a holley 4180 with 600 cfm, will the HOLLEY 670 CFM Street Avenger Carburetor Part #: 0-80670 fit and work properly?

67mustang302

Yes, it should fit and work. But you prolly don't need 670cfm. I'm running the 570 on my 302.

my94pony

ok, i dont know holley told me that what i should get when i called them im just making sure because the guy didnt sound too sure

67mustang302

They told me 670 too, and when I asked them why they never answered. Keep in mind that if you accurately calculate carb size it usually ends up being smaller than you think necessary. Also the cfm flow rating of the carb is at 1.5" Hg depression. So you put a 500cfm carb on an engine that pulls 2" Hg vacuum at WOT and it'll be moving around 580-620cfm through that 500cfm carb. Also, the point of the carb is to atomise fuel, and to that extent the smaller carb has an advantage, better metering signal and better shear. Again though, you have to consider how you use the car as well, if most of the driving is at lower rpm, the smaller carb will have better mileage and low rpm power, and also better throttle response(sometimes). Basically you need a carb that is large enough to not restrict power, but small enough to promote good atomisation/shear and throttle response.

Gearing and vehicle weight play a factor as well.

mjr46

600 should be adequate for a stock or mild build

WhiteWindsor

While i agree that a 670 cfm might be a little overkill. These street avenger carbs are very tame and street friendly. If you plan on future upgrade's i would go with the 670. The slighter bigger avenger will not hurt you on your engine now.

1985stang

Just get a standard holley 4160. It's 600 cfm, and basically a direct replacement of the 4180. I love this carb. It's extremely reliable and it runs great for not evenbeing tuned yet (will probably do that this summer when i have time). You can also find awesome deals on them, i got mine for about 200 bucks + shipping,brand new off ebay.

67mustang302

Keep in mind as well that a vacuum 2nd carb on a dual plane intake will tolerate a larger cfm.