Testing a Intake manifold?

Hey guys, im in the process of designing a Turbo Plenum... this time round for a Turbo 4cyl but would be looking into making a intake for a Holden 6 in the future...

But yea just wondering if guys with a flowbench to test heads would they also be able to test a intake manifold? I mainly want to test that when Air is blown in under pressure that each runner is receiving equal amounts of air... so one cylinder isnt running richer/leaner then the others...

Im not sure if it matters but most flowbenches work under vacuum dont they? and only test 1 port at a time?

Would somewhere be able to push air in and test all the ports at the same time? or would it not make a difference and be fine to just test each port individually under vacuum?

P.S. if there is anyone here who has had alot of experiance with custom plenums lemme know. (and yes I have Corky Bells Maximum boost

The usual way to test a manifold is to bolt it to a head and test each port individually. The flow with the manifold fitted is compared to the flow of the bare head port. After all this you will end up with a percentage flow drop for each manifold runner. It doesn't really matter if the air is pulled or pushed through, so long as it's in the right direction. Any porter should be able to do this for you.