1988 Chevy Celebrity Timming is off

Not sure on what to do it sounds like the timing is off but is has a coil pack. We thought the timing had jumped so we broke it down redid the head had a valve job done it dont have a timing chain its gear on gear they looked good so we didnt replace them. We did check to make sure that part was lined up using the marks on the gears while it was top dead center that part looked good we got it all back together it still has a knocking but not as loud we think the timing been off is causing the knocking some what so how do we double check the timing with it having a coil pack