Ok, the main problem is that there's no timing marks, everything has to be just right and there's absolutely no margin for error, the F4r is possibly one of the hardest engines to time up and if you get it wrong, the whole top end is scrap and potentially the bottom end too in worst case scenario.
Doesn't end with the cam timing either, the aux belt and tensioner/idler should be changed at the same time, and if that isn't done or not done properly, you risk aux belt failure, which will knock the cambelt off.
It really isn't worth it. If you get a specialist to do it, you're not just paying for the job to be done, you're paying for someone to blame and foot the bill if there is an issue (providing everything recommended is done)
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