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Hi guys, I’m in the process of swapping a 6.0L LS into my 69 Chevelle and the last thing to tackle is the oil catch can/ breather set up.
This is about 500hp n/a motor, that will be street driven. My valve covers both have a barb type fitting on them.. What type of system are you guys running, or what would you suggest?
is a system that hooks up to a vacuum source really necessary for a N/A set up??
TIA for any help with this,
Scott.
Last edited by 1972LS1Camaro; Aug 25, 2025 at 07:16 PM.
Reason: Added photo
I have those same valve covers but I removed the hard lines and drilled and tapped for 3/8 NPT to 10AN male fittings and connected both lines to a breather can. This was for my 01 car and I did dual breather cans on the 99 car. I didn’t want to run PCV and utilize the intake port to pull a vacuum on the crankcase. Nope not for me, only fresh air through the throttle body enters my intake manifold for it's air/fuel mixture. You may be able to get away with standard 3/8" hose off of both valve covers to a breather can but it may be a little restrictive.
Another thing you could do is to leave them as-is and run a sealed catch can and use the intake manifold and throttle body or the air induction tube and run PCV. From the dtiver side valve cover through a sealed catch can and then out of the can through an inline PCV valve just before connecting to the 3/8" port on the intake manifold. For the passenger valve cover run a 3/8" hose from it to either the port on the throttle body or install a port on the bellow or air induction tube in front of the throttle body and connect the 3/8" line to it.
Last edited by 01CamaroSSTx; Aug 25, 2025 at 08:36 PM.
quick question what pulley setup/spacing are you using I'm slowly gathering parts for my 69 Chevelle swap and i like how you have the compressor on top
I have those same valve covers but I removed the hard lines and drilled and tapped for 3/8 NPT to 10AN male fittings and connected both lines to a breather can. This was for my 01 car and I did dual breather cans on the 99 car. I didn’t want to run PCV and utilize the intake port to pull a vacuum on the crankcase. Nope not for me, only fresh air through the throttle body enters my intake manifold for it's air/fuel mixture. You may be able to get away with standard 3/8" hose off of both valve covers to a breather can but it may be a little restrictive.
Another thing you could do is to leave them as-is and run a sealed catch can and use the intake manifold and throttle body or the air induction tube and run PCV. From the dtiver side valve cover through a sealed catch can and then out of the can through an inline PCV valve just before connecting to the 3/8" port on the intake manifold. For the passenger valve cover run a 3/8" hose from it to either the port on the throttle body or install a port on the bellow or air induction tube in front of the throttle body and connect the 3/8" line to it.
thank you for the reply, I might be thick, but I’m not sure if I get it yet.. lol
Last edited by 1972LS1Camaro; Aug 26, 2025 at 08:12 PM.
quick question what pulley setup/spacing are you using I'm slowly gathering parts for my 69 Chevelle swap and i like how you have the compressor on top
it’s a Holley set up, I’d have to dig out the instructions but I believe it’s their mid mount set up.
is a system that hooks up to a vacuum source really necessary for a N/A set up??
Many ways to do this but they can all be summed up to 2 options for crankcase set up. Vented or evacuation.
Vented just relieves the crankcase of any blowby pressure. Crap option but many chose this for the simplicity and cost.
Evacuation is preferred since it will constantly pull fresh air through the crankcase. Keeps the basement and oil clean. This requires intake manifold vacuum and using a catch can will keep that air going into the intake clean.
Many ways to do this but they can all be summed up to 2 options for crankcase set up. Vented or evacuation.
Vented just relieves the crankcase of any blowby pressure. Crap option but many chose this for the simplicity and cost.
Evacuation is preferred since it will constantly pull fresh air through the crankcase. Keeps the basement and oil clean. This requires intake manifold vacuum and using a catch can will keep that air going into the intake clean.
Simplicity and cost?..Hilarious!
Have you seen what a quality ventilation system looks like that truly does benefit an engine? This kit allows you to ventilate the crankcase without sending that CRAP back into your engine!
And one more thing..Explain to me where this fresh air that everyone keeps saying is coming from? It's the same CRAP coming from both valve covers only the passenger side is also mixing with the real fresh air, you know that air coming into the intake manifold by way of the throttle body but the vacuum port on the intake that you use in PCV setups is where most of the CRAP comes from..
A sealed catch can does help keep some of the oil from making it's way back into the manifold and that's a plus. Mighty Mouse Solutions has systems out there to aid in keeping that CRAP from getting into the engine because some of those systems utilize a breather to ventilate to atmosphere but to say that ventilation by using a breather can that could even be tied into the collectors to aid in sending those nasty byproducts through the exhaust is a crap option obviously dosen't know how PCV really works because truth be told it's doing the same thing just using a different path to get there and that path is through your engine.
Last edited by 01CamaroSSTx; Aug 28, 2025 at 03:52 PM.
Are you retarded? Fresh air comes from atmosphere. Filtered air before the throttle blade, filtered with a breather or from a catch can. This is air IN to crankcase.
Are you retarded? Fresh air comes from atmosphere. Filtered air before the throttle blade, filtered with a breather or from a catch can. This is air IN to crankcase.
Vented does not evacuate, learn the difference.
Maybe you have problems with comprehension. Installing a vacuum pump to draw the blowby gases out of the crankcase and then ventilate to atmosphere is the even better option.
The crap gets caught in the catch can. Nothing goes back into the engine. If it does, return your Temu, Amazon or Ebay can and get a good one from Mighty Mouse, Racetronix or Motion.
Anything getting past a good can means your engine is punched beyond good or your set up is not pulling crankcase fumes from a good spot. Need decent baffling.
Unless you are confused by the original reply. I am not against venting but it does have it's drawbacks. The is zero evacuation with this method. It only relieves crankcase pressure.
It will stop 99.9% or enough of it to where it will NEVER be a problem. Daily drivers reach the end of their life with NO catch cans with zero issue.
Neither system is perfect but no evacuation is harder on a crankcase than allowing 0.0001 ppm into a big V8 under boost that is inhaling 2000 cfm of air a minute.
Not sure if you are just here to argue but your facts are being considered but everyone should know the truth about EACH system.
Do what you think is best for your engine and I'll do the same. It's been over 20K miles since my build and I'm not the least bit concerned about the affects of PCV or the lack thereof in my performance engine. I've talked to plenty of people on the subject regarding this. In closing I'll just say that my stock vehicles have PCV and I know they can go many many miles with factory PCV but I also know what affects it can have on them too.
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Oil breather options. 
