OSRIC is a very faithful reproduction of AD&D - playing it will give you an excellent feel for AD&D play. There was one AD&D rule that I'd never even noticed until I saw it called out more clearly in OSRIC (namely, the rule that gnome fighter/illusionists are limited to leather armour).
Personally, I would suggest starting with Moldvay Basic if you can find it. (I believe Labyrinth Lord is the retroclone of that edition?) It has quick PC generation, clear rules, and good GM advice for dungeon and scenario design.
Any classic edition is going to feel very sparse on the action resolution side compared to 3E/PF or 4e (or even 2nd ed AD&D played with all the trimmings), because of the absence of skill rules. Both AD&D and Moldvay Basic have rules for combat, movement (but not much on climbing, swimming or jumping), for light sources, for searching at and opening doors, and for finding traps. Anything beyond that and you are pretty much on your own.