2001 Chevy 2500 hd 6.0
 

I need ideas on what mods I can do somewhat affordably to my truck.

What is your budget and what do you want to do?

The "mods" you can do are endless really. Anything from exterior to interior or engine and drivetrain.

In something that heavy, weight reduction or changing the rear end gears depending on your current tire/gear combo can do wonders. Or even just a tune with bolt on's in you want more power.

Like what kind of injectors should I put in and what would be a good option to rebuild the top end and put in a cam

Injectors are only something you change if they can't supply enough for the power the engine is making. They don't add power themselves and should be picked based on how much power you want to add.

There is nothing to really "rebuild" on the top end, not much to a LS V8. It's an intake manifold that sits right on the cylinder head. If you have bad lifters, you could remove the heads and replace those but it's not something you have to do. Some will swap them when doing a cam swap and some don't.

Do lots of reading on camshafts and what you are getting yourself into. Consider your goals and what stall converter you want as well as how you want the engine to behave.

Staying mild with a 212/218 camshaft size with new valve springs and appropite size pushrods is always a good cam choice. You'll need around 31-33lb/hr injectors to know you have plenty of fuel. Factory 8.1 injectors or 33lb/hr factory flex fuel injectors from a mid 2000's silverado/sierra/tahoe/suburban. All the injector data is out there to grab from factory tune files.

You'll need a tune as well. Then think about exhaust if you want it. I'd say budget $1,500 to $2,000 to do everything.