I had my 400 rebuilt 6 months ago. I put a Holley 2300 model 500 cfm 2 barrel carb on it. I have the fresh air hose from the passenger side valve cover going the the breather, I know it needs clean air, it has a vacuum on it...

the PCV valve pushes the fumes out of the motor, right? so do I need a vacuum source on it with it pushing it out any how? I did have the PCV valve on the valve cover in, but no hose running from it to the back of the carb, I had great take off power, now with a hose running from the PCV to the back of the carb, I hardly have any take off power and my motor wants to die when I put it in gear.

one more question: if the PCV pushes the fumes out of the crank case, wouldn't putting a vacuum source that is stronger than the force of the air pushed out create blow-by on the rings and pistons because of the suction force?

 

and I have a bigger than stock cam. if that helps about vacuum pressure

 

it goes to the large vacuum "nipple" on the front on the carb

 

the PCV sucks the crankcase gasses out, vacuum is a suction force

just make sure your power brakes are hooked up to their own vacuum source, don't connect the PCV or anything else to the same connection as the power brakes

 

the power brakes are connected to a T fitting thing on the back of the intake manifold, the other lines that are on that same fitting is modulator valve line and the heater/ac selector in the cab. what would have caused lack of power with the PCV hooked up to the carb and a lot of power with it not hooked up to the carb?

 

yeah Ford uses the Vac Tree for the brakes, modulator & climate controls, but some guys will Tee off the brake hose and connect the PCV and a couple other things... not good

why the PCV would cause so much difference IDK? is the PCV valve stuck open, split in the hose or hose not sealed well to the nipple?

 

new PCV valve, new hose, and it seals great.

Roll Tide!!!

 

The PCV (POSITIVE CANKCASE VENTILAION) valve uses manifold vacuum to reduce crankcase gasses which are mostly combustion gasses that get past your piston rings, without the PCV system the gases would remain in your crankcace to contamiate motor oil and create sludge, when working properly the crankcase needs fresh air which in most cases is connected from the intake air cleaner to the opposite valve cover after being sure this is working properly check for vacuum leaks . For a very good idea of engine condition try check manifold vacuum and adjusting your carb with a vacuum gauge. Check Accelerator pump for poor off the line performance.