pistons, heads, both?

thanks for all the info. im familiar with engine building. its just the mopar specific details that i want to make sure about. ill probably use the magnums. i can do all the machine work at work. i ve built a few engines but im still new to performance. the stall im running is a 2200 b&m. the gears right now are 3.55s. id also like to go to a lower gear. maybe 3.90s or 4.10s. i also have larger tires for the rear to compensate alittle. the intake i have is a victor single plane. im on a college budget so id like to use as much as i got. theres no way i can afford to drop $1500 on a set of heads. the magnums i got for free and they are on a running engine (has a knock tho) so id really like to use those.

thanks