The Mini Ram is good, but i think the Holley Stealth Ram is considered a bit better for most applications. Here is a good post from another forum, someone who has supposedly tested all four TPI-esque intakes on the same engine:
http://forums.hybridz.org/showthread.php?t=67411
Other places have published similar results. Here is another site with the flow numbers:
http://www.stealthram.com/flowcomparison.html
Again it does depend on displacement, cam, and intended use. For 350 to 383 sbc with moderate cam, the Stealth Ram will have the same top end and better bottom end torque. For larger displacement and/or really big cam, the TPIS unit might be the better one.
However, if you already have it, i'm sure it'll work very well, especially on a 383.
Good luck!
Paul