I've dug around on this quite a bit and it's probably smartest for me to simply port the stock intake manifold. I understand, honestly.
However, porting the stock manifold makes a really boring, not very instructional class project and so I'm building a new manifold from the ground up.
The plan is to make the manifold as adjustable as possible, since we are unlikely to be able to design it correctly first try. To do this I was planning to build it in three pieces:
a) A base with weld-on injector bungs and a place to bolt the fuel rail.
b) Four round tubes that bolt onto the base plate.
c) A plenum that will mount a vacuum block and bolt to the four round tubes.
With this design I can swap the tubes any time I like for different runner lengths. Maybe even end up with a torquey street set and a higher rpm track set.
Does this sound like an intelligent approach?
Should I just copy the plenum volume of the stock manifold or is there a rule of thumb for plenum sizing?
I've seen three styles of plenum on four cylinder engines. A sort of blob that looks like this:
A log style manifold like this:
And finally, a sloping log like this:
There are also snail type manifolds, but I lack the tools and skills to build them.
Any ideas on which type of plenum I should use?
