the larger the plenum, generally the more upper end power. The plenum is like a capacitor for the engines air and fuel requirements.
A larger plenum can also make up for a smaller throttle body, the smaller the throttle body the more on the large side you will want to go plenum wise.
Ive seen quoted as a general rule of thumb that a plenum should be 1.5 times the displacement of of the engine. Course depending on the setup that could be higher or lower some people like it to be 1:1 ratio, some higher.
I dont know the plenum volume for a mini ram but your standard single plane carb manifold is typically undersized in the plenum department for most applications |