about a month ago my intake manifold started leaking water, i put some stop leak in it and it quit leaking. but it still loses water, can it be leaking into the engine?

 

Yes, it can leak into the engine.
Intake manifold gasket failure is a notorius problem with the original design gaskets on the smallblock Vortec engines. Basically, the gaskets are a plastic frame with a silicone bead. The plastic distorts and cracks from inconsistencies between the intake manifold bolt torques.
The new design gaskets includes metal inserts around the bolt hole to prevent the gasket from being crushed. Only the GM gaskets have this and other design improvements, so buy the gaskets from GM.

 

the new GM gaskets are nice, i just had to replace them on my V8 and also on my wife's V6 in her xtreme.....it took me 2 hours to replace them on my wife's xtreme, as far as mine i'm not sure should have taken about 3 hours just b/c it was the first time, but i had my heads refreshed and put 1.6RR in too so i had to pull my heads to drill the pushrod holes.....you should get them changed asap