Your looking for a 420a engine. 420a engine's came in the Eclipse RS and GS models 95-99. A GST engine is totally different, those are 4g63t. Not a drop in engine for a RS or GS model Eclipse and would cost over 3k to have the swap done and truly is not worth it. For that type of money you might as well buy a modded 1g Turbo Eclipse/Talon/Laser or save a little bit more and buy a 2g 95-99 GST.