I didn't know what thread to post this to, so here we go. I have a '05 Phase II short block mated to a '97 Phase I DOHC head. I am going to change the timing belt at the 60k mark, however I read that newer EJ25s are 105k interval. Could one assume I have the parts to meet the 105k TCI criteria?

 

My 2c worth: The timing belt's life will be determined by 2 factors, firstly its make up, i.e. materials and its construction. Secondly by the fatigue it sustains during its life (milage) which will be determined by the amount of bends it sustains on its round and round journey. So if you're using a new modern belt than you can expect the new milage interval for replacement. Now for teh fatigue part, does the new setup have more bends?? i.e. dual cam over single cam? or are you going to be reving it twice as much as a family car over the same milage? anyway you get the picture.

If all else fails it's always best to be safe than sorry