Heads should be way better than stock with the valve size and CC. Along with heat properties and combustion chamber size and will allow for more compression without detonation. I should be fine on vacuum but I'd if not I have options. I have a set of brand new manual lines for no booster and maybe a wilwood unit or other upgrade later. These allow for much more lift than stock heads and duration. Biggest upgrade is the induction it's not low end as many think. A 34 HP or so gain and more torque with a stroker kit when top end is left stock. Cost to do all the port and bowl work didn't add up for the gains with stock iron head and valves were not 2.02 intake. But it's just a inexpensive build up I won't have but maybe 3500 or less in it.