the 850 is a competition carby. used on sports sedan etc etc bigger 350's you go the 950 and drag go over the 1000.dont use a 850 on the street motor,and you wouldnt put an 850 on a motor that made under 580hp-620hp or so and to get that you are going to be spending big dollars.if you give me the the engine specs ill tell you what carb will be best for what you are doing. the annular is a competition carby which has a better flow and yes round flow.its the carb we used on sportsedans 10+ years ago. as they say old hat,but still good for a budget.
mick