I'm pretty sure 300zx injectors are 370cc.
Just some very rough/estimate calculations on my trusty calculator (can I sound more like a nerdy engineer <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt='
'> ) says 270cc's are good for 5psi, 370cc's are good for 12psi, 444's are good for 17psi, 550's are good for 25psi, and 720's are good for 37psi. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'> Of course, this only for a rough idea...don't take it as gospel or anything.