PCV & Pwr Brakes into same port?

[jimmyray]

I have a Holley 750 dp to go on my M1 airgap single plane manifold. My Carter has 2 ports one each in front & in back, back for Power Brakes and Front for PCV.

So I ran the holley without hooking up the PVC, and proceeded to blow oild all inside the engine compartment; that was silly.

Anyhoo, can I put in a T and hook up both to the same port on the Holley?

 

[jimmyray]

any thoughts?

 

[RedFish]

I wouldn't > I'd be afraid motor oil would destroy the diafram in the brake booster. You might delete the pcv if your local regulations will allow it.

 

[ramcharger]

If I was running a single plane with no vacuum tap and power brakes (which I wouldn't), I would drill and tap the manifold for a vacuum tap.

I suppose in a emergency a T would work, but I would not suggest using it long term.

Is this a serious strip/street car or is the engine a high mileage modified stocker?

The reason I ask is that a single plane manifold work best in combination with a cam that pulls such low vacuum that power brakes are ineffective. It's all about the combo as everything must work together as a team to produce power in the rpm range that works best with your rear end gear and tires/suspension.

 

[jimmyray]

Its a 1000 mile 408 stroker, specs:
408 cast crank stroker from Hughes
9.9:1 compression
93 Octane gas
mild port/polish on Edelbrock perf heads, closed chamber, fresh valve job
M1 single plane airgap with gasket match (heads too)
Edel 1406 600 cfm carb, vacuum secondaries (want the Holley!)
Comp roller .544/.541 236/242 110 centerline
FBO ignition, ditributor curved to 16 inital, 34 total @ 2900 rpm
Hooker comp 1 5/8" headers (dented bottoms on driver side, naturally) 3" collector
2.5" pipe to flowmasters into 2" pipe (looks to be OE) into a-body tips
3000 stall TCI streetmaster
727 manual reverse
4.11 sure grip 8.25"

Overall, a fairly well matched combo, that pull 8-12 inches vacuum at 800 rpm idle. I guess I could just vent the motor, and eliminate the PVC (duh..did not evem think of that). Power brakes seem to work fine, just need to maybe bleed the fronts, as the rears want to lock under hard braking (dry road!)

The reason I put a PVC on was my high mileage 340 was having a lot of blow by and I thought it might help.

Good point, RedFish, about the oil damaging the Power Brake diaphram - did not think of that, either.

So, opinions on just venting both valve covers with filters and eliminating the PVC?

 

[ramcharger]

Your carb is way too small for that combo, but I bet it would scream with a Holley 750+ cfm double pumper.

I would run a pcv on any car run on the street. If you dont want to drill and tap the intake, drill and tap a 1" carb spacer.

I've driven cars with power brakes and 10" of vacuum and it's not fun in traffic, be careful. Have you thought of using a vacuum resevoir?

 

[ted_sweet]

i ran my car with a T as you want for years with no problems.

 

[doktor_x]

A vacuum reservoir in conjunction with an electric pump may work well. You may be able to rape a junk Cavalier (redundancy with relevance) for the pump. I don't know if they all had pumps, but I had a 1982 w/ the fabulous 2.0 liter that ran one.

Just a thought.