This winter I am going to fabricate my own aluminum intake manifold.

As to the plenium, how large should I have it? I've heard that you want it to be about twice the displacement of your engine, but I'm not 100% on this. Also, should I incorporate velocity stacks inside the plenium, or how should I smooth the transition between plenium and runner? I've been trying to look at designs from other companies, but I can't find anything that will help me. Thanks,

Colin

 

there is so much design that goes into intake manfold development and its not just a go with this and it will work. Some swear by box plenums which others swear against etc.