Does anyone know how close the ports on a B16 Vtec and a B18 Vtec are?

I'm looking at a B16a mani and trying to see how close a B18 mani of any sort would be to matching up port wise? I can make an adapter or just re-drill the holes for the bolt holes, so long as the ports are within say, 2-3mm of each other. I've got a full scale machine shop through college if I need to use anything so drilling/notching a few holes isn't a big deal.

I am going to go to the local JY probably here soon and compare intake manifold gaskets to intake manifolds and see what I come up with, but I figured someone might know anyway. Thanks.

Nick