An 850 is not too big for a 440. What is the stall of your converter? Have you tried tuning the 850? Any changes, like aircleaner?
Greg…converter is 9.5” dynamic that stalled about 3800 rpm. Ranit at the track without an air cleaner…but no other tuning really other than (10 years ago) adjusting idle mixture for max vacuum. Now rebuilt it after sitting and it won’t idle at all…😂
