325 is not an extremely large head. Especially for 500 cubic inches. I got canfields 320s on my 496. Same bottom end kit as you.Car has plenty of bottom end pep. It will only remotely hook up on the street.Even with a set of 33x16 goodyears aired down to 6 psi and a vht "prepped" area in front of my house.Far from being "lazy" or "sluggish" from running too big a head. I dont believe the 325 will kill the motor at all,but a set of 290s might choke it down pretty bad if you decide to go big later. All depends if this is gonna be the last set of heads you will EVER buy for this motor,or if you wanna leave growing room. And be honest....we all need growing room :wink: