can a person 6'0 fit in a 300zx

That changes it a bit.  A 6' tall passenger should be fine.  passenger side has more legroom.

I'm 6'2" and drive an 85 Z.  Plenty of room.

im not sure about the older z31 model but i drive a 1996 and im 6'0 foot and there is alot of room to spare

my uncle os 6' 2 and he doesnt have a problem fitting in his 300zx

no problem, i have a z31 and it has enough space for that and taller easy

im 6'3 and i fit just fine as long as there are t-tops he should be great

Just get him a pair of goggles, take the t-tops off, and have him hang on, i hope its not a LONG trip, but that should be more enjoyable. .. Ya he will fit in the passenger side :-D 6'0" isn't that abnormally sized, i'm 6'2" and i drive a 90 300ZX

im 6'2 and have no problem siting in my 96' 300zxTT (and there is a good 3-4 extra inches space). there shouldnt
be any trouble.

im 6'3" and my dad is 6'4" and we can both fit in our '86 300z