i went through this before
as far as i know for the thick diameter tube, they were two different length tubes but no more
my engine needed the 250mm long tube, and that was NLA
the one that was available was the 300mm long
so i got it manufactured by a shop, he did me 4 tubes, (250mm) just in case
check that your case is the correct lenght
as to the position, check it with the intake manifolds, and place the tube according to the support that hangs from the mentioned manifolds, front one
this supoort is a triangle shaped plate