I’ve recently did a swap on my 02 camaro ss i got another ls1 from a 04 gto I have everything thing connect, but I went to do my first oil change to see if there was anything in the oil and it was mixed with water and water was over flowing in the water reservoir no oil was in the radiator or reservoir what should I look at first this is my first build I did myself , the engine was running before they pulled it from the gto so I don’t think it would be the heads or a crack in the engine.

 

Hate to say it but it sounds like a head gasket,hopefully not a warped or cracked head.
One other possibility might be the intake is sealed improperly.

 

I still have my old heads from the original engine should I switch the heads out along with new head gaskets ?

 

how do I know is the intake is sealed improperly anything I should look for specifically because when I put it on I made sure it sat right and level before putting the rest of the stuff on but it is my first build so there should be mistakes

 

Back in the day I worked on my own stuff a lot,simple carbed engines.
These days with EFI etc. it's all mostly over my head,that and I just don't have the time so I pay others to work on my stuff.
If I remember right (that can be an issue at my age (lol) LS motors can be a bit tricky to get sealed right.
I can't say I've done one,did lots of old school small and big blocks but none of this newer stuff.
Hang in there,there's some folks in here that know the newer stuff much better than I.

 

appreciate it lol yeah and it’s a headache when your on YouTube learning from there but practices makes perfection,

 

There are tests you can do, you want to start with a leak down test. If they seem ok then it is an intake issue or something is cracked. Search you tube for how to do a leak down test. You may be able borrow a leak down tester at a parts store but you will need a small compressor.You could also borrow a coolant pressure tester with the plugs out you could just see coolant coming out of a plug hole.

The down side is if the motor ran with coolant in the oil you may have ruined it. If it was pure water then there is much less chance of damage. Antifreeze does not play well with bearing. If you didn't run it with coolant did the last owner?

If you bought the motor from junk yard junk give them a call before you do anything. Most motors have a 30 day warranty but you want them to guide you on how they want to proceed. If the head gasket was blown bad while it was in the GTO then the motor could have been over heated bad and could have all kinds of damage. Junk yard may scrap that one and find you another one. The yard knows if it was a bad over heat the motor could become a money pit.