Starter does not disengage properly

[GasCan II]

Hello guys
I just installed a brand new starter on my 1997 5.7L LX Bravo motor #OK 147937. The new starter was ordered by serial number but it does not disengage properly, the starter gear hangs up in the flywheel gear for a split second when the motor starts. After research seems it may need shims. No shims came with it and no shims where used on the old starter.
Any ideas ?
Thanks for any help.

 

[Scott Danforth]

buy starter shims, follow the recommendation on shimming the pinion.

 

[GasCan II]

Thank you Scott im going to try the shims.