This picture clearly demonstrates the discrepancy between conditioning between the two
Arnold shows much clearer and defined separation in the biceps , triceps , traps , infranspinatus , teres , and lats and all three head of the deltoids , neither have any detail or development of the leg biceps and Arnold's calves are again showing better detail
This coupled with posing is exactly why Arnold won , Sergio looks better from an aesthetics stand point because he has a better structure , smaller joints , rounder bellies , etc but he's still an unfinished product , like Paul Dillett his posing & presentation were terrible , like Flex Wheeler he relied to much on his genetics to pull him out of trouble and that may have worked with , Poole and Sipes but not with Arnold