Recommended 4bbl carb for stock 318

Hey, Sorry I've been away for a bit.
First I should start of by saying, thanks for the input.
And I was actually hoping to find a period correct carb that would have been used on small block Mopar's and had reasonable reliability, power and economy. I am aware that 1973 318's never had 4bbl's and that the Carter BBD was the best option for 2bbl, but I'm hoping to maintain the look of a stock small block with a bit more power.
Also, it seem everyone has the input of jumping to a high CFM compared to a big 2bbl or smaller 4bbl. I didn't realize this was the goal is size for power and economy, I would have expected around 400CFM. I do have a Holley 850 Double pumper.... I wish I had a cam and pistons and intake for that thing.
So why 600CFM? Is there much gain in horse power and economy over a 400CFM?
Also there seems to be a discrepancy in the Edlebrock that most are happy but one said they can ice up? I do live in a cold climate so in the winter I do start it up every so often to keep everything lubed. Has anyone else had this kind of issue?, I never seen this on a stock carb, so I can only assume it's due to thin aluminum?
And on top of all that I really need the cost to be as low as possible and still get quality.

Thanks
Chad
I would offer you the previous carburetor and the intake it came off of for $50 + shipping. Not sure if that helps ya or if your even interested. Just thought I would offer it in case you might wanna try it. Proly kinda expensive on shipping but I have no clue as never shipped parts before.