For dragracing I would build a big bore engine. you can make more horsepower with a highcomp. piston and port job etc.
But you can make a lot more torque with a big bore kit, and you need a lot of torque for dragracing, and maybe a lock up clutch.
I have build my engine with an Athena 480 big bore kit and only a 12,0:1 piston. It jumped only a few horsepower but a lot more torque, and the torque is peaking already at 6250rpm´s