I have a stock 1960 283 small block in my impala that was originally a 2 barrel. It now has an Edelbrock 4 barrel intake without the front oil fill tube or the option to mill one out. The block does have the rear breather tube that run down the back of the engine between the transmission. I would like to put on a set of the 60's corvette finned value covers without the fill holes. If my intake doesn't have a breather/fill tube but has the rear breather will that be sufficient for the crank case pressure? Or do I need to run a front breather intake manifold? The 283 is a stocker, no cam or head work and I can always take the valve covers off when I change the oil.
If you don't put a breather inlet tube on it somewhere, you're gonna blow oil out the valve cover gaskets.
Sounds like it still has the road draft tube installed, which will allow pressure to pulse, but will not replace crankcase vapors with fresh air. Not the best plan, but should not over pressurize the crankcase. It would be best to allow fresh air in, either with a breather tube or breathers in the valve covers. Not to mention, how are you going to add/change your oil? Pull a valve cover? Often times valve covers can be found that already have offset type breathers installed on Corvette or other solid top valve covers. Devin
I would sell the manifold and get the proper type as edlebrock does offer it , like 4 pedal said how you going to change the oil??? , and the fresh air that replaces the old vapors helps carry out the acids and excess flammable vapors that the oil/gas generates too .
I think that's the best option to try and get an original early manifold or the Edelbrock one that has the front fill hole you can mill out. I have a set of valve covers I want to use and hate to cut them up for the breathers
If you get a intake with the oil fill tube, I would get rid of the road draft tube and replace it with a pcv valve like GM used in the early sixties. My original 63 Impala has one that is like this one pictured from showcars. It will help a lot in keeping things cleaner under the hood.
Drill out the intake with a hole saw and install an oil fill tube. Then use a cap for it, with a breather element, so it lets in air there, and keep the road draft to let the pressure out. As it was intended originally.
Installing a Positive Crankcase Ventilation (PCV) system is more than just venting the block, it's about keeping the oil and the interior of the motor clean by preventing the build-up of combustion byproducts including carbon and water. These unwanted byproducts are effectively "vacuumed" out of the engine by the PCV system, not just "vented". This is your perfect opportunity to install a PCV system, why not take it?
I did the same Modded the Edelbrock Performer with the oil fill tube and added the PCV at the rear of the block via the carb base. Runs like a champ. rb base.
First off get your terminology straight. It will help when figuring it out. A road draft or a PCV system is not a "pressure relief system". The purpose is to pass air through the crankcase. Air enters through one breather and flows through the crankcase carrying fumes and moisture with it as it leaves the crankcase at the other breather. If you are setting up a custom system, determine where you want the air to enter and where it will exit. think about the flow through the engine Notice the arrows and how there is a direction for the air flow through the block. It took a long time for the hotrodders to realize that a PVC system is a good thing for an engine. This is a 49 -53 flathead but it shows the desirable airflow through the engine. They knew about it then and nothing has changed.
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