What I have learned by looking at this Gates Timing Belt Guide Book...
http://us.lexusownersclub.com/forums/index.php?app=core&module=attach§ion=attach&attach_id=9725
People say that the 1990 to 94 are non interference, and everything after that is interference. Well, after doing some research that is partially true. The 1990 to 1997 actually has the same exact engine called 1UZ-FE. Also uses the same timing belt part number as well. That engine seems to be non-interference. However, the 1998 to 2000 are called 1UZFE. Notice there is NO dash between z and f. The 98 to 2000 is a completely different engine as far as valvetrain. So, the username, " eds92sc," has mentioned about the 1998 model LS and SC400 motor vehicles receiving a new engine with continuously Variable Valve Timing with intelligence (VVT-i), this is the 1UZFE interference engine. I hope I was able to shed some light on this matter.