GaryC

Brief overview: I have a 350 (383 stroker) where the engine is circa late 80’s early 90’s, in my 63. The valve covers are the 4-bolts down the center type with one cover having 2 ‘accessories’ holes and the other cover has one. These are new GM covers to where there was nothing in the ‘accessories’ holes yet. So, I have an oil-fill cap in one hole. In another hole I have an oil breather cap, which I think I should take off. I do not have anything in the third hole.

My concern is, what emissions configuration should I go with? I don’t think I have to have the same emissions that were configured in the car that the 350 came out of. I think that I have to try and duplicate what was in the ’63.

The original 327 motor has a hose going from the air cleaner to the oil fill tube in the intake. I am not going to be using the original air cleaner or intake so I do not know if I should worry about this connection with a new after-market air cleaner.

The 327 also has a PCV valve that goes from the intake to the rear of the block. It connects to the block using a tube that is pressed into the block. The 350 block does not have the hole in the rear for this tube. I was thinking of installing a PCV valve from the intake to one of the ‘accessories’ holes in the valve cover. I believe that this location in the 350 valve cover is the same as the rear of the block of the 327. Correct?

That just leaves me with one ‘accessories’ hole with no connection which I assume that I could just use another oil-fill cap. Or, should I be doing something else?

Does anyone have other suggestions? What have you done or seen others do with respect to emissions when taking a newer motor and install it in an older vette?

Thanks for the input.

Gary

SWCDuke

You need a functioning PCV system - something that is often overlooked. Since the
350 blocks do not have the rear breather hole provision, you'll have to go with a rocker
cover to rocker cover system. Assuming your carb has a vacuum port for a PCV system
you can probably used the rocker grommets and valve from a 350.

Duke

GaryC

The carburetor (and the intake) has a port that I can use.

Your suggestion is what I was trying to describe that I thought would be the best solution.

Just so I am not missing anything, when you stated "a rocker cover to rocker cover system", where you stating that I needed a line to both rocker covers?

Also, I assume that I should not be using a oil breather cap if I go with the PCV unit, right?

Thanks for the input.

Gary

SWCDuke

You rig one line from the downstream side of the air cleaner to one rocker cover. and
the second line from the rocker cover to the carb port. The PCV valve should be in
this second line. Some fit into a grommet on the rocker cover, some thread into the
carburetor, and some are designed to clamp between sections of vent hose.

With this system architecture, clean air enters through one rocker cover, circulates through
the engine and exits along with blowby vapor from the other rocker cover.

With this system the oil cap should be sealed. The PCV valve provides both metering and
backfire protection to the crankscase. Without some sort of anti-backfire device, a backfire
can propagate to the crankcase and cause an explosion because the crankcase vapors
are usually combustible.

Duke

GaryC

Duke,

For the 'first' side (air cleaner to rocker), could I use the oil breather (filter) cap instead?

Gary