Help with PCV setup
 

I have a 455 that is getting new aluminum heads, rpm intake and a 4150 carb. I plan on upgrading to the aluminum valley pan with pcv from Butler. The bottom of my new carb has a 3/8 port in the rear and a 3/16 port in the front, there is no ported vacuum on the carb. I will include some photos.

My current setup I have a breather on both valve covers not hooked to anything, and then the pcv goes to the front port on the iron intake.

I need to hook up my brakes, hei and pcv but have no idea what to do about the pcv. I have those two ports on the baseplate and one in the back of the rpm.

PCV is--ideally--connected to the primary side of the carb via a 3/8 nipple, so that the fumes are distributed as evenly as possible to the two planes of the intake manifold, mixed thoroughly with the incoming air stream. That way the fumes go as equally as possible to all eight cylinders. Next-best would be to duct the PCV fumes to the rear (secondary side) of the carb via a 3/8 nipple, and again distributed to both planes of the intake manifold.

The LAST thing you want to do is to connect the PCV fumes to one runner of the intake manifold, so that the fumes go primarily to one cylinder--a disaster at idle, and not that great at any load or RPM.

OTOH, a brake booster can be connected to one runner if necessary, because when that runner is receiving air from the booster, you're off the throttle and the cylinder isn't under load.

DO NOT TEE the booster and the PCV together! Keep 'em separate until they join the intake manifold/carb body with their individual 3/8 nipples.

Many Holley carbs are cast--but not machined--for a 3/8 nipple suitable for PCV or brake booster. Post photos of your throttle-body casting WITHOUT the base gasket in place. A 3/8 drill bit, some 3/8 seamless steel tubing with a bead crunched on one end via a tubing flare tool, a drop of Loctite 271 or 242, and you'd be ready-to-go.

This is a custom carburetor built for me that I will not alter. I have a 3/16 front port on the baseplate and a 3/8 rear port. The rpm intake has a port on the rear manifold by the distributor. So maybe I hook the pvc to the rear 3/8 port on the baseplate, the hei to the front 3/16 port, and tap the rear rpm port for the brake booster. Will there be any decline in vacuum for brakes?

My pvc right now is hooked to the intake, guessing it's in one runner.

I plan on upgrading to the aluminum valley pan with pcv from Butler.


Are you using the Tomahawk valley pan with the PCV? I beleive on my 4150 I used that 3/8" port on the rear of carb to feed my brake booster before going to hydra boost.

I thought they had an aluminum one, they don't. I will keep my stock valley pan as I am using 1.5 roller rockers. I was planning on using the rear carb plate for the brake booster, but that would leave me running the pvc to the rear intake port on the rpm.

They have Aluminum but not with PCV as far as I can tell. If you decide the Tomahawk is a great pan. If you don't use the PCV you can always put a plug in it. Becareful with your old valley pan as dirt gets trapped inside the two layers of metal. One other thing to be aware of is if using hydraulic roller lifters the can hit the stock valley pan.
I was also thinking you could connect the PCV to the rpm manifold at the back.

Curious, What heads you going with? Looks like your already having issues with your power brakes. I see a black vacuum can attached to the booster.

My heads were actually just done today. Edelbrock heads milled to 80cc, 10.5:1 compression. I have hydraulic lifters now on my current setup without issue with the stock pan.

Schurkey said not to hook it to the manifold. I am waiting to hear from Butler as well.

I have hydraulic lifters now on my current setup without issue with the stock pan.

I'm referring to Hydraulic roller lifters.

Curious also if your going with adjustable valve train with the new heads?

I am not planning on it as the geometry should be OK.

Well, I'm my opinion you with still have to check pushrod length and valve stem pattern to make sure everything is ok. Also be sure to check your rocker for any interference with the new head springs and retainers.

Before I had my current set up, I no longer have a brake booster, I fitted a nipple for the booster into a 1"carb spacer therefore allowing the carb nipple to be used for the PCV

Did you have the stock intake? The rpm already raises everything 1.25", I don't think I will have room for another inch.

If you have aftermarket heads or changed the block deck height at all, you cant use the pontiac non adjustable valve setting of just tightening all rocker nuts to 20lb/ft... you need to do the standard SBC/BBC adjustable valve procedure with crimped lock nuts or poly locks. Also rocker arm ratios dont influence what valley pan you use, thats for hyd roller lifters on egr valley pans. .

The issue with stock valley pans for hyd roller lifters is only on the later EGR pans, the early non egr pans will clear most roller lifter/cam options, unless the cam lift is very high that can touch a stock pre egr pan, but you can just slightly dent the bottom in a couple areas to clear the lifters in that case.. per ken Ace brewer & many others that have used original non egr pans on hyd roller lifters.

My Butler pan w/PCV sucks oil like crazy! It is well built but has too many holes and no amount of baffled grommets, tube extensions resolved it. Gave up just run a breather now. My old KRE one thinner aluminum but only 3 holes did fine. My new 455 on the stand I used a Tomahawk pan from Butler. It did have to be "massaged" in the corners to seal.

Shurkey said not to run the PCV and brakes together-what most sources say-but the 383 SBC and a Victor Jr I autocrossed in the Camaro(before the IA motor) did fine running it that way. If the manifold has a port in it-especially in the plenum area vs a single runner is the ideal- it is better so pulling extra air does not make the one run leaneer. Also remember the factory at . HO racing recommended if running the Torker I to tap and drill a hole for a barb fitting in the center of the plenum so it is common in the plenum. Torker II has a port in the back already drilled and tapped. Also remember the old RAIV/HO intakes fitting actuall went into the top AND bottome plenums!

Get the Tomahawk valley cover. It's a duplicate of the factory unit. With anything else it will suck oil in thru the PCV valve. Butler sells the Tomahawk and they do clear for roller lifters.

The PCV valve is a calibrated vacuum leak.

A vacuum leak into the brake booster vacuum hose reduces the amount of vacuum delivered to the brake booster. If your engine develops enough vacuum to overcome the vacuum leak and supply the booster with sufficient vacuum...it'd work OK.

I still think it's a bad idea.

Not "perfect" but should function just fine.

That's a mess. All the fumes tend to go to one cylinder; that cylinder runs lean and at lower octane due to oil contamination. May even cause lean-misfire at idle.

No. It was an RPM manifold.