re headers

[Celica RA45]

bob when you say short primaries or long primaries are we still talking about 4 into 2 into 1 or just 4 into 1
i have a set of pipes here that make power to 9000 rpm and the primaries are 800 mm long and the secondaries are very short 300mm
dia are 50mm then 55mm and 60 out to 75mm mandrel to the back of car