Attachment 12948my DF will do 80 , when the air temp is 45 degree's or so , and struggles to do 70 when its over 100 degree's , so yes temperature of intake air indeed makes a difference

negligable indeed , only a 12-15% speed increase from running colder air , but its the diff from cruising a highway and having to take the access road

I shift into 5th at about 68 indicated my ratio says I should float my valves at 85 , but I cant get but a hair over 80 in perfect yet very cold conditions

bob r u running stock sprocket ? that will make u top out at about 50-55 when your valves start to float making u unable to go faster