Well 300 hp is a piece of cake with any small block Mopar. I have never swapped a 360, in favor of a 273, 318, or 340, let alone think of one as the only high performance option. But I do agree to use what you have. Unfortunately his 360 is of unknown condition. With 360 heads, Edelbrock carb, 4 barrel intake, dual exhaust and a cam in the 268 duration ball park any small block will easily do all that he is looking for. Especially with 3.91 gears and the 833 O/D manual trans. First gear gives a torque multiplication of 3.91 x 3.09 = 12.08 and a high gear equivalent of 3.91 x .73 = 2.85. Even my 273 would spin the tires through 1st and 2nd.