Nice wheels! Never seen pics on an S14. There is a member with a set on his Y33.
Genuine FR500 wheels built by Ford are 18x9 +24mm. Most replicas come in 17x9, 17x10.5, 18x9, and 18x10.
Try to find an online Ford parts site for the genuine ones. Gene Evans Ford is an example.
http://www.gefracing.com Another member posted this site for replica wheels
http://www.50resto.com