If it's 10 degrees off, you are lucky 10 degrees off in one direction will cause piston/valve contact. 10 degrees in the other direction will kill power.

Whenever you mess with the timing chain on these cars, you must pull the tensioner, push the ratcheting plunger all the way through and then reinsert it so that it can ratchet into place without being too tight.

Good luck and Merry Christmas,
Larry