A little confused between whether you're dealing with a /6 or LA
According to master Tech, all '70 California cars got the Vapor Saver system
http://www.imperialclub.com/Repair/Lit/Master/271/Page11.htm


There's a slight difference in the bowl venting from /6 to v9
http://www.imperialclub.com/Repair/Lit/Master/271/Page13.htm

'70 Service Manual probably has more detail