could really use some input
 

I have a 32 blackfin with twin 8.3 cummins 6cta 420HP engines.
I noticed a while back the port engine was sounding bad and blowing smoke.Pulled the valve cover and number 1 cylinder both push rods were a quarter inch short from hitting the rockers.Mechanic told me i needed a new camshaft.
well i ordered new cam and tappets and installed in the boat.turned the motor over after everything was put in and now there is a sound coming from the front gears.It sounds like clanking or bells.I pulled the and checked it and there is zero lash between the gear and the cam.I feel like my gear is bent or got bent when the machine shop pulled off the gear and put on a new one.I ran a piece of thin paper around under the gear and the gear is hitting the gear housing.Looks like ill be pulling the cam back out and checking to see if my gear is bent.
Has anyone else here ever had this issue or is there something else im missing.Is it possible for the machine shop to have pressed the gear on to far.Im up in arms on this one.
I spent 50 dollars on boatdiesel.com membership and have absolutely no help with this entire issue other than pull the motor and tear it apart.Pulling a diesel from a boat is not an easy task.