So what's everyone's opinion on crankcase evac kits on a pretty stought street/strip 440 or just run breathers on valve covers?

If you run muffs dont bother with evacs...reason
why.. a evac will pull about 5"hg max so if you
have muffs on the car every inch of back pressure
the muffs have is 1" less that the evacs will pull
and if your muffs are greater than 5"hg you will
pressurize the crank case with exhaust

Makes sense, breathers it is. Thanks for the info 👍

Mister P, how/where do I measure the muffs (vac difference in/out?)

Tap in anywhere forward of the muffs... use
a "HG gauge.. can use a psi gauge also

what if you were to tap in at the end of the exhaust pipe after the muffs. would there be any vacuum there?

No.. but your trying to measure the pressure
before the muff.. that pressure is back pressure
on the engine

What are the merits of a PCV system at this application?

They are great for cruise rpm.. no help at
WOT

Pictured below is my preferred setup. Just -10 lines from each valve cover to a breather tank like you'd use for a vacuum pump setup. Works great.

I have a vacuum pump on my hemi and don't really care for it. Saw no change in performance. Wish I'd just used the same type of setup I have on my wedge motor.

an8sec70Cuda...what type of oil rings are you running?? If low tension do you remember what the tension was rated at in lbs?? Thanks

Had both in the hemi and saw no real difference. The current rings are low tension (18 lb).

I have a electric vac pump sitting on my bench
that I was gonna put on the Rampage.. but I dont
like vac pumps on a street car.. I run 2 breathers
on it and no oil comes out of it.. but they are
baffled

What would be better, just run breathers or the an line to a catch can like an8sec70cuda showed? Or about the same either way? My valve covers have no holes so I will have to drill them and have no baffles.

Does anyone make a catch can that can be used with header evacs?

The evacs could draw from the top of the can and the breather lines could enter somewhere midway up the can. This way it could still create vacuum but any oil would be left in the bottom of the can to be drained later?


Make sense?

I like the lines and can b/c there's no leaks like you get w/ breathers on the valve covers. They'll drip oil everywhere.

This is similar to what I was asking except you would need 2 tubes top and 2 tubes bottom. Or you could T them I guess. I have never tried it but seems like it would work and any oil drawn through the breather would end up in the bottom of the tank.

Correct me if I am wrong.

I use to make my own separator cans at work
(I used them on fuel) but its simple... I put
both lines in the top with different lengths
of tube inside the can with the short one being
the exit(to the engine in your case)

Moroso make oil/air separators.

Tex

I run a PCV and pan evacs. Before I bought my muffs I spent some time on the phone with them. They said as long as the pan evac is after the muff it will work. That's how I did it. The engine is sealed, the PCV pulls at idle and cruise, the PCV and pan evac at cruise and wide open.