650 AVS for 318

[7duster4]

Right now I have a 500cfm edelbrock performer on my 318. It's a rather mild build with 9:1 compression. I have been told by many people the carb is too small. I have been looking for a slightly used 600cfm performer. But my question regards the 650cfm thunder avs edelbrocks. From what I have been told they are more tunable. Would those be overkill for my 318? Would a 600cfm be better? Does anyone here run one on their 318. Too bad they don't make the thunder series in 600, but they make them in 500.

All info is appreciated. Thanks.

 

[rumblefish360]

I run what they say is rated at 625 cfm, a Carter emissions AFB. I have not looked for any difference's in this carb and the 600 series carb. I do not see any with the naked eye. I also currently have a 600 Hholley on top of a 318 now. (Swapped for fun.)

I have no issue with this size carb on the 318 and it does work very well with minor mods and some small aggressive ones. A 500 works great with a stock engine and bolt on performance parts.

Put a vacuum gauge on the engine and when driving down the road, have a buddy notice if the gauge pulls any vacuum at wide open throttle.
Anyting above .5 and the carb should be larger.

Also note, I have done a few engines that have pulled 1 - 1.5 of vacuum on the gauge and the swap was worth only a ave. of 10 HP up top accroding to the dyno. It is a combo dependent thing. The more mello the combo, the less of a gain.

 

[70aarcuda]

with a mild 318, i would not spend the money to go from 500 cfm to 650 cfm...

i drove a 318 dart around with an edlelbrock 600 afb, only cause i converted from a 2 barrel to 4 barrel and bought a new carb at autozone down the street.

i now have that carb on my 73 duster...

 

[7duster4]

with a mild 318, i would not spend the money to go from 500 cfm to 650 cfm...

i drove a 318 dart around with an edlelbrock 600 afb, only cause i converted from a 2 barrel to 4 barrel and bought a new carb at autozone down the street.

i now have that carb on my 73 duster...

How do you like the 600? Probably isn't much of a difference between a 500 and 600.

 

[ramcharger]

I wish I could help you on this one but I'm a Holley guy. Not so much that I think that they are better, but that's what I know.

 

[7duster4]

I got some friends that prefer holley over anything else. The edelbrock has been great as far as dependability. But I know Holleys are much better for performance.