7.8 timing

Hello, rebuilding a 7.8 and after I line up the timing makes on the cam and crank gear with the idler gear and spin the motor by hand the lines never line up again. It's that normal for the way they sized the idler gear or is there something I'm missing about timing this particular motor being the one I've over ever witness in line this with an idler gear. Thanks for the help.

That's normal, if I rotate the engine before installing the pump gear I'll pull the idler back off and realign the gears to get the pump timing correct.