Swapping intake and exhaust manifolds

[Ted K.]

I have a mid year with Edlebrock intake and carb, and headers. I would like to make it look more correct and have a period correct cast iron intake and cast exhaust manifolds from that era for a swap. The question is the block is a 400 block from 1978, will all the old parts fit?

[Richard G.]

Re: Swaping intake and exhaust manifolds

Ted;
Yes they will likely fit.
What makes SBC fun. The parts will fit but some shouldn't.
If you are in a warm climate I would block off the heat riser ports.
You can purchase a gasket to do this with. Many gasket kits come with the steel plates that can be inserted.
It ill keep the manifold looking new.
I would recommend powder coating the intake for extra durability.
Don't forget to add sealant to the through bolts on the intake.
Forgive me if I have stated the obvious.
Has to be some advantages to getting old, made most of my mistakes already.
Best of luck to you.
Rick

[Paul D.]

Re: Swaping intake and exhaust manifolds

The problem with mid year valve covers and intake on a late model engine is getting it to "breathe" without a working PCV system. Late model engines vent the valve covers to the air cleaner on one side and through the PCV valve to the carb on the other, creating a path to vent the crank case. Without this ventilation, you will probably suffer numerous oil leaks. Search this forum as well as that "other" forum for info on how some have cleverly hid a PCV system under the intake in the lifter valley. I think it draws air in through the intake mounted oil fill tube with a breather cap and then pulls crank fumes through a oil separator mounted under the intake (like used with a draft tube) and piped through a fitting mounted to a hole at the back of the intake then to the carb.