1' spacer under carb

mario03srt said
A single plane on a mild 318 does not sound like a correct combo to me.

I did a poor job of information there. What the Edelbrock tech site said was open spacer worked better on single plane with more power higher rpm. (I'm running a performer dual plane) The four hole spacer will give you better low end power but will suffer at higher rpm. It's not often I ever take mine over 4500 rpm so if I can increase my lower power that would be great.
I agree with jah64 when I installed avs-2 650 a couple of years ago my secondaries were hitting my heat spacer and not opening up all the way. I took spacer out and did some carving to make it work.