Toyota FJ Cruiser (GSJ10/15) in install with 1GR-FE engine, unlike other GR series of engine, which is consider more popular, like for 4GR-FE in Toyota Mark X and 2GR-FE in Toyota Vellfire, the 3,956cc 1GR-FE engine most probably is seen in Toyota FJ Cruiser only in Malaysia market, although there are others Toyota model that using 1GR-FE engine which you can have a look
here,
Interestingly, both 1GR-FE and 2GR-FE have the same bore diameter of 94mm, which their different is the stroke for 1GR-FE is 95mm and 2GR-FE is 83mm, but their head gasket have different part number, they looks very similar, and may need put 2 gasket side by side to check on their differences.
