Hey builders just saw this CB350 with a different tank, look like a cbr250rs or such tank, any may give you a different outlook for a tank.
Rod from OZ 8)
http://cgi.ebay.com.au/HONDA-CB350-CLASSIC-RACER_W0QQitemZ280413891075QQcmdZViewItemQQptZAU_Motorcycles?hash=item4149f86a03#ht_780wt_1167