MtuRbo2..... the 300hp mark was achieved in the 60's with the mustang, but im assume you are talking since the 80's. The 1968 Mustang CJ with the 428 plolice interceptor engine had 360hp and ran the quarter in 13.56 at 106mph on the polyglass (shitty tires) tires. as far as the late models are concerned the first mustang to top the 300hp mark was the 1995 cobra R, but that wasnt mass produced (250 cars). in 1996 the mustang cobra got a 305hp 4.6. your welcome.