Due to little unconsitencies on machine work, not everything is exactly where it should be, Most production things have a plus or minus tolerance, if your crank key cut was on one end of the scale and your flywheel cut was at the other, it would add up to the timing being way off. Do your self a favor, buy or borrow a degree wheel and check your timing off that, shoot for 30 before top dead center. Plenty of post on here on how to do it.