My Chevy big block in one of my rods is stroked, it's bored, has a Crane roller cam. Also runs GM Performance aluminum heads. It runs strong, very strong. I do see a small amount of blowby but very light amount when the oil fill cap is removed.. At idle it only has 9.5 inches of vacuum. My present PCV is an Auto Bone special most likely overseas product. I'm wondering about using a GM PCV part number 6487779. I believe it was used on older performance Big and Small blocks and is also recommended for the GM Performance 572" engine. What do you guys or gals use on your warmed over BB Chevy's? Will an incorrect PCV effect blowby?
I was never a fan of ingesting that back into my combustion chambers. I just use breathers to the open air but also wouldn't rule out evacuation tubes in the headers or into a catch can, anything other than mixing that into my air/fuel mix.
oh, there's nothing wrong with sucking the crap out of the crankcase, and burning it. Better than leaving it in there to corrode stuff, and turn the oil to muck. I usually pick one of the high perf applications for stock PCV valves on mine.
I was just reading a post for a 235. Capping off all ports (pcv, breather, vacuum line) and measuring the vacuum at the dipstick to find out what one you need to run. It also gave a link to an adjustable pcv.
evac system. Big jugs swinging around create a lot of crank pressure. https://www.enginelabs.com/tech-stories/tech-how-external-vacuum-pumps-free-up-horsepower/
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