Drew ,
I am still AMAZED at how little people REALLY know about carburetors! The FIRST thing they do not understand is the "principal" of how they WORK. MANY talk about "flooding" an engine with a 715-750-850 etc. In truth , a given engine will only flow what the cubic inches , intake and exhaust efficiency and RPM allow. Bolting on a 600 may be an easy way out for some , but I'll take an expertly optimized carburetor any day.
To this day, one of my most thrilled customers argued with me about what he needed for months. 350 Chevy with a 600 double pumper, ran like poop everywhere, got horrible economy, etc etc. He finally relented and I sent him a 780cfm carb that I custom tweeked. Better economy, ran better everywhere. He went from ready to sell the car, to wanting to sell his daily driver so he could drive his corvette more. Lol. I mean, the guy was fanatical, sent me all sortsa gifts, etc.... kinda funny actually, tho I pondered a restraining order for a little bit.
Agreed with the flooding comment. You are much more likely to have overly rich issues with a 390cfm carb than you are an 800. I'm not sure how people do not understand what I consider to be common sense, but I also ignore a lot of people. I have one of the greatest books ever written about carburetion, by Walter Larew. I gave a copy to a competitor. With some of the best info in his hands, he misread it and came to mostly wrong conclusions. The same is present here in this thread.
Ohh, Randy, I sent you an email regarding the carb from the Original Poster.... it is super cool, check it out and save the photos for your records.
Drew