Cheapest way to built a 300-350hp small block

going to be starting a 69 valiant build for a driver that my girlfriend and myself will drive pretty often. and she will drive at the drag strip when we go. looking to get the car in the mid 13s with a 904 trans and 3.55 gears in an 8 3/4. im looking to build a cheap and simple small block with 300-350 hp. what would you guys recommend? looking for it to have very mild street manors. I have a set of hooker headers and an edelbrock performer intake and a 650 holley. i think it is going to have to be a 360 because of cost and availability. was even thinking junk yard 360 and leaving the bottom end alone. just new cam, timing gear and oil pump.

lets here your recommendations guys.