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Discussion Starter #61
An engine with a big cam needs a bigger orifice in the valve because there's less vacuum to create airflow at idle.
I use a Lunati Voodoo roller cam (201207-10LK) and Lunati roller tip rockers (85035-16). It is not a loping cam, but it does have some performance specs. The lobe separation and duration is 262/270 and lift is .507/.515. I don't really consider it a big cam. I wonder if the exhaust has any bearing on the size of the PCV valve as well. I am using the original heads and original 2.5" rams horn exhaust with 2.5" 'H" exhaust system.
Bob
 

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Great post and great troubleshooting suggestions..always good to get other people’s experiences, may be something you never thought of and glad the OP had success.

Never really thought about pcv valves either but hmmm. Is there a formula or just trial and error?

Have a 265 bored .030 over, 305 crank, 305 416 heads, Lunati cam and lifters(hydraulic flat), edelbrock performer intake and 1405 carb. Msd rtr, patriot 3/4 length and 2.5 dual with cherry bombs. Wouldn’t even know where to start without just throwing different valves on it
 

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Discussion Starter #63
Great post and great troubleshooting suggestions..always good to get other people’s experiences, may be something you never thought of and glad the OP had success.

Never really thought about pcv valves either but hmmm. Is there a formula or just trial and error?

Have a 265 bored .030 over, 305 crank, 305 416 heads, Lunati cam and lifters(hydraulic flat), edelbrock performer intake and 1405 carb. Msd rtr, patriot 3/4 length and 2.5 dual with cherry bombs. Wouldn’t even know where to start without just throwing different valves on it
Hey Phil, I'm the OP, and my suggestion is if it ain't broke, don't fix it. The yellow and black Chev below my signature has a Power Pack 265, and the black '56 has a 300 horse 327. I am not about to start experimenting with PCV's. They're great drivers, and as the saying goes "Let sleeping dogs lie". :)
Bob
 

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Hey Phil, I'm the OP, and my suggestion is if it ain't broke, don't fix it. The yellow and black Chev below my signature has a Power Pack 265, and the black '56 has a 300 horse 327. I am not about to start experimenting with PCV's. They're great drivers, and as the saying goes "Let sleeping dogs lie". :)
Bob

Truer words never spoken haha. It’s been a good runner for 3 years now but guess I’m just trying to tweak things. Switched to pure gas about a year ago and have had a ridiculous amount of soot coming from my tailpipes on startup I’m trying to wrap my head around. Everything else looks and works great no difference except the gas. Hmm doesn’t burn oil, no smoke, just a blast of soot on startup, 2 nice stripes on the garage floor.

Sorry I didn’t mean to hijack your post..just curious about the pcv sizing and if there’s a way to figure it. It’s really the only thing I can think of and wondering now if maybe I don’t have the right size. Pretty sure the one I got is for a 305 since I have so many 305 parts I just went with that.
 

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Discussion Starter #65
Truer words never spoken haha. It’s been a good runner for 3 years now but guess I’m just trying to tweak things. Switched to pure gas about a year ago and have had a ridiculous amount of soot coming from my tailpipes on startup I’m trying to wrap my head around. Everything else looks and works great no difference except the gas. Hmm doesn’t burn oil, no smoke, just a blast of soot on startup, 2 nice stripes on the garage floor.

Sorry I didn’t mean to hijack your post..just curious about the pcv sizing and if there’s a way to figure it. It’s really the only thing I can think of and wondering now if maybe I don’t have the right size. Pretty sure the one I got is for a 305 since I have so many 305 parts I just went with that.
No problem Phil. There's room for all. It sounds like you're running too rich. I don't know what you mean by "pure gas", unless you mean 100% octane. I see you live in Kentucky. They may sell a blend of gas I'm not familiar with. Try adjusting your carb a little leaner.
Bob
 

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Here's a website from a company that makes em. There's certain links you can use in there to get to some different types of info. In one of them somewhere it mentions stalling when the engine comes back down to idle. http://mewagner.com/

 

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No problem Phil. There's room for all. It sounds like you're running too rich. I don't know what you mean by "pure gas", unless you mean 100% octane. I see you live in Kentucky. They may sell a blend of gas I'm not familiar with. Try adjusting your carb a little leaner.
Bob

Thanks I’ll give that a try. It’s gas with no ethanol. Some stations scattered around and the boat guys and classic car guys like it..also good for mowers and chainsaws and such that the ethanol attacks. Running regular 87 with no ethanol..farm boy helped me with the numbers and says I’m around 9.5/1 compression with my setup and that I should be gtg with reg unleaded with the hardened seats and such with the 416 heads.
 

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I had that problem on my old engine 327 I have a 350 now and it still quit when
putting on the brakes and coming to a stop I have the Edelbrock 600 with the
manual chock use no more than 5 psi for fuel pressure I am using 4 psi and the
stalling problem is solved connect pcv to valve cover and 3/16 hose to distributer
I have a Mallory Unilight for 31 years.
 

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Discussion Starter #69
I had that problem on my old engine 327 I have a 350 now and it still quit when
putting on the brakes and coming to a stop I have the Edelbrock 600 with the
manual chock use no more than 5 psi for fuel pressure I am using 4 psi and the
stalling problem is solved connect pcv to valve cover and 3/16 hose to distributer
I have a Mallory Unilight for 31 years.
Mine would begin to stall as soon as I let up on the gas, causing a jerky feeling when I was shifting.
Bob
 

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I had that problem on my old engine 327 I have a 350 now and it still quit when
putting on the brakes and coming to a stop I have the Edelbrock 600 with the
manual chock use no more than 5 psi for fuel pressure I am using 4 psi and the
stalling problem is solved connect pcv to valve cover and 3/16 hose to distributer
I have a Mallory Unilight for 31 years.
I also have a '70 El Camino 350 on my 57 with the 1406 electric choke carb.Every one in a while i check and set with a vacuum gage connected to full manifold vacuum.Also i have the dist. vacuum advance connected to the fitting in front for full manifold vac. The other one is for timed port vac. for engines that have their emissions stuff like EGR etc. The PCV is hooked up normally to the LH (drivers) valve cover. :anim_25: :bowtieb:
 
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