340 build help

Alright so here's the new info. The 340 I recently bought has good compression in all eight cylinders. Pulled the heads and intake and its very clean. Turns over easily. I stated before but ill say I again for info sake I saw the engine run in the previous car and it was really quiet with no unusual noises. Now... I don't think I'm doing a rebuilt so what can you guys recommend for easy bolt ons in order to bump up the horsepower and torque? Thanks guys!