Hi there every one I'm going to install some cams in my boss 260 engine just wondering if its a must to replace the oil pump or will it be ok to leave or if I did do it how hard is it to replace it with the motor still in the car I have had the motor out once before but it looks like a completely different story to replace the oil pump with engine in the car just with the front timing cover off

It's easy to replace the pump with the engine in the car but getting the pickup back on is not fun. I managed to do it but it would easier if you dropped the pan. If you've got fat fingers you'll likely have to drop the pan.
Not much space down there to get at the two little bolts....

Ok that's what I thought its going to be a pain in the a*** to get
To and put the pick up back on is it possible to take off the sump while the motor is in the car

Yeah I think the sump will come off in the car. You probably don't need it to come right off but you would to clean up the gasket properly before refitting anyway. Good thing about modulars is their excellent gaskets which don't need replacing generally.