Apparently the 1980-81 series 626 RWD with a 1300 cc SOHC motor had a rachet tensioner and it fits the FJ with minor modification to the back profile (compare your mazda tensioner with the nissan one to see what you have to remove with a file or die grinder). The mazda part number for this is 3953-12-500A, but make sure you bring your FJ top tensioner with you to the mazda parts store to check out its the right one before you hand over the $. Then get out of there real quick just in case other mazda parts are infectious....

The rachet tensioner is slightly more difficult to install than the nissan one, as the rachet keeps taking up, but if you use a bit of wire to push the little lever out (once you get one you'll know what I mean), it goes in like a breeze. I think the mazda part should be made general knowledge and even put in the specs page as a must do upgrade, as I've been using them for around 10 years now and have virtually forgotten what that FJ chain rattle sounds like....... Yeha !