if you don't have porting skills, at least 3 angle valve job and remove swirl brows. you can open ports a little with sanding rolls and flapper wheels. i was careful and opened them about .1" and polished them. blending transition from bowl to port helps. be patient with swirl brows to avoid cutting into the side of chamber. you only have about .020 to get to sealing surface. i deshrouded my intake about that much. blend the valve seats then get them cut (3 angle) you will see the valve seats are recessed slightly. i also opened up the chambers slightly i an attempt to leesen the angle the gaases have to change to enter the port. i polished them with 600 grit flapper and compound/cotton. i straightened out the exhaust port a little in an attempt to reduce gasses change of direction. it is probably benficial to get the gasses exiting at 90 degrees, so to that purpose i ground the left side of the exhaust port at the exit. if you purchase stainless race valves 1.80" and get them back cut there is more there. or....
you can purchase 4v or 3v heads.