I watched 1Road on YouTube and he added a catch can to his suburban. After 300 miles he had a inch or more of oil in can. I installed a can on my 2004 Tahoe 5.3Z (new rebuilt motor) and after 300 miles nothing. I installed on bank1 from rear valve cover (no pcv), to input on can, the output in can back to intake.

Does some / new engines in good shape just not have oil escaping from valve cover to intake? I am happy if no oil but am worried I missed something?

 

Back in the day ( I'm an OG) we used to call "problem" vehicles, built on a Monday or a Friday, due to Monday morning hangovers and Friday's being ready to be off work for two days, LOL! You must have a motor put together on Tues, Weds, or Thursday. LOL! I know it' a rebuilt motor.

Seriously I would not worry about it. Besides that, the persons who rebuilt your mill likely did a good job on it. 300 miles is nothing. I can drive that far in half a day. Your engine is not even broken in yet, it sounds like to me. You've no need for a catch can, without DFI, but that was your call. I run a 2015 Malibu with DFI, and have not installed a catch can. I likely will not since the motor is still tight and uses up no motor oil yet.

 

an inch at 300 miles...he probably has excessive blow by

 

Yeah, the guy with the Burb has lots of blow-by for sure.