My 18 Bl in ported box. it is in an SUV so should i have the sub facing the roof with the port facing the back?

maybe

yah man that sounds the best my buddy has 2 18 bls in ported box with the port to the back and the subs to the roof sounds great

I have my sub and port firing up in my van and i think it sounds good.

i have sub back port up and sounds good in my scion xB (not to much trunk space few inches from hatch)

And every car is 100% different so again the only answer is maybe. You need to try it in different positions, but of course if you are a lzayfuck you could just give up and do whatever. I guarantee whatever won't be as good as you trying different things though.