The crankcase need a way of equalizing pressure. The pistons are moving up and down moving air around. In the old days it was just vented to the atmosphere, road draft tube, valve cover breathers. Air can be sucked in so there needs to be some sort of filtering if outside air is introduced. Oil vapor is also being blown around. If you let it slow down is will settle out and not be blown out, think catch can. A PCV valve is only a one way valve that allows pressure to escape. It is released into the intake and any oil/gas vapor is burned.

Modern dragsters use vacuum pumps to reduce pressure in the crankcase to reduce hp loss due to windage.

 

I found a couple of pix of engines I worked on back then. In the top left, the black hose coming out of the front center of the Quadrajet carb is going to the PCV Valve in the right rear valve cover grommet.

In the bottom picture the PCV grommet in the front of the right valve cover is hard to see and its PCV valve and hose is not yet installed, it connected to a tube in the base of the Holley, either center rear or on the right rear side of the Holley baseplate. Its intake hose went from the air cleaner to the left valve cover.

I have another picture that I can't find, of my 402 cu in big block that had the PCV in the left valve cover and its intake was a chrome breather in the rear of the right valve cover. I''ll post it later when I find it.

The man sitting behind the engine is a chopper pilot who flew flat out with his hair on fire every where we went. He drove his Vette pretty hard too. He was one of the best pilots I ever flew with. I can remember the inside of every engine I ever worked on except this one. It is possible that he had the engine built at a performance machine shop in Savannah and I did the r&r and tear down on it. The blue Vette he owned had full race suspension with oil coolers, and though I never raced him I rode in it.

I can tell you it went like a bat out of hell and cornered better than any Vette I ever rode in at that time. I'm pretty sure it had a roll cage with aircraft seat belts also. I believe it was a solid cam 327 with more than 350 hp stock. It had a Crane street grind cam and valve gear plus the truck load of speed parts he bought for it. The block was balanced, decked, line bored and I remember matching the intake ports to the manifold.

I was letting my girl friend drive my 67 big block north on Abercorn when he pulled up beside us and gunned his engine. My girl freaked out and floored the gas (45 mph in 4th gear). I was stunned to see my speedometer go past 120 while my tires went up in smoke. I knew it would blow if she got it much past 8,000 so I turned off the ignition and we waited for it to stop spinning the tires. She didn't know I turned it off and kept the gas on the floor as he got out of there before it fishtailed and maybe hit his car.

 

I found the picture of my 402 big block. You can see the PCV grommet in the left valve cover and the chrome breather on the right valve cover. The engine came out of a 70 Chevy Nova. I had the crank, rods, and pistons balanced. I matched intake ports and a 5 angle valve job with Crane triple springs and retainers. Crane pushrods finished the valve gear and a lightweight aluminum flywheel allowed the engine to rev very quickly. I had to mix Pontiac starter armature and coils with chevy nose cases to start it using a big truck battery for the amps. The stock Chevy starters burned up trying to turn it over. Ignition was a Vette transister amp and distributor out of a salvage yard. It could smoke the tires at any speed in any gear.

 

Jebby, that is sort of how my 327 was in my 66,

Sjhanc,
Thanks for the old pics, thats my thing, old school and vintage, survivors, modded or stock,

Im in eustis fl, a few years ago tina and i and a buddy came up to willison, a member there didnt like the 454 in his wifes 73 so i swapped him my 383 as i didnt like its high rpm power band, he did,

We did the swap that day crashed out then buttoned up the loose ends and came home the next day, i love that 454

Thanks all for coolness and camaraderie, and a bit of learning,

i posted as i have these old school valve covers with odd breathers jb welded in,



I wanted this old motion cal custom style and was happy to score them for 35.00,
My plan was to put steel wool in one breather and seal the other to a pvc valve, but i was hoping to get other cool ideas on some unusual looking set up,

Or should i remove the odd breathers and go a different way?