when installing in stock ls1 i have a ls6 oil pump from my full ls6 but motors blown could i use that or does it have to be ported like mandatory to do?

 

I'd at least go through the pump and inspect it very well, if not replace it. When engine's blow, it's not uncommon for some metal shaving and/or debris to go through the pump and cause issues. It'd be a shame to put it on a new engine and see that investment have problems due to that pump!