Salam...i came across this randomly on some website...was doing research for my engine which is a 1G-FE...
Btw which 1JZ you talking about? Because i guess there are quite a few different ones...1JZ-FE, 1JZ-GE, 1JZ-GTE, 1JZ-FSE, VVTi, 1JZ-GE VVTi, 1JZ-GTE VVti...
This might be of use to you regarding the letters after 1JZ or 1G: "The 'F' stands for 'fuel economy' or something, the 'E' stands for 'Electronic Injection' as opposed to carbureted engines. The "G" stands for sportier engines, which is determined by the angle and size of the valves. The 'F' engines have smaller valves and the 'G' engine has bigger valves. To make a long story short, stay away from FE engines as long as you can and always go for 'G' engines."