The King of Grain is Ralph Gibson, look him up if you haven't heard of him. And his recipe is Tri-X rated from 100 to 400 (so normal or over exposing), Rodinal mixed 1:25 at 68F for 11 minutes with 10 seconds agitation every one and a half minutes, and if it makes a difference he rolled the tank on it's side. Taken from 'Darkroom' by Lustrum Press. He got pretty normal exposure times for his negs (minus dodging and burning of course), and went on to print them on Brovira grade 4 and 5 so making the grain pop by avoiding those annoying mid tones.
Most film scanners, Epson V700, Plustek, Nikon 9000 etc will easily resolve film grain, but at the same time add digital noise on top. It's a skill in itself to process negatives that suite a technique of scanning at low contrast to help in some measure avoid digital noise, but if you want to show authentic grain and don't have a darkroom I'd recommend going down the camera route for film 'scanning'.