minimum. And do not paint the portion where the gaskets go (just an FYI) or the stem that holds the timing pulley. I have done beautiful porting jobs on plenums (upper and lower) and have had people screw them up with as little as rattle can. Tape of the plenum and powder coat.. my first preferance. If no powdercoating avail. Shoot it with a high heat 1200+ degree paint. Whatever you do also, don't shoot any paint into the intake tracks (yes, someone has done it before.) It's cracks, chips, melts and goes into your cylinder and isn't very fun for the engine.