Welcome to CHR! If you're going for nice street power in a keeper car, you might want to consider one of the newer LS type engines. Available new or used with hp ratings in the 400 range and still very, very streetable and decent on mpg, too!!! As Stude mentioned, it's going to take more then just hp, don't forget the rest of the drivetrain and also the brakes should be upgraded to match the new go power. Also the 3rd Gen 'maros need some chassis upgrades, too. Subframe connectors, an improved torque arm, and relocating the lower bars forward mount points is a good plan. Oh yeah, and don't forget new shocks, struts, and suspension bushings. Lots of horsepower will only end up being a parts killer unless the rest of the car is upgraded to handle it!!!