Color me simple minded, but have you tried pulling the belt off of the crank and re-zeroing the crank? Before making drastic time-consuming steps, that's probably what I'd try. The jumped sprocket theory seems most likely to me. The dizzy and cam timing marks line up correctly, right? Getting the belt on correctly can sometimes take a couple of tries (in my experience, anyway).

Just my .02

73
-Jon
KJ6GVM

As seen on Expedition with TX plates: VEGETARIAN - An old Indian word for poor hunter

Grampa's Trooper
1974 FJ40
1987 FJ60