I have an everyday run of the mill 350 sbc. this weekend i am changing the heads out from the stock ones to a set of 882s with 3 angle valve job and ported and polished. 882s are not what i would consider good performance heads since i have a set of 441s with the valves cut out to 2.02 and 1.6 but not ported and polished. plus i dont want to go and try diggin them out of the barn. I am also going to bolt on a set of long tube headers, painted, nothing fancy. And a K&N air cleaner. But the K&N is for more longterm cheap use over hp. What kind of power gain am i looking at if any? Im thinking maybe 10 to 20 hp. p.s. next year the truck is getting a fresh 383, airgapper intake, th350 turbo, aluminium pulley set, 600 cfm carb, slightly above mild cam, msd ignition system, 2000 stall converter, full roller shaft rockers, so im not too worried about the power gain with the heads and headers, just curious.