[455-4+1]

Jim Robertson, RACE.
Start with the correct 48 casting (there are a few). He will point you I the right direction.
We were successfully running heads up with SB Cheby iron head offerings from Dart and Pro Action with a set of Jim's Dports on 412 max cubes.
Some of these engines were from world class engine builders like Marsh here in NZ (personally held worlds fastest Carbed small block ET and MPH records) so no easy feild to qualify in let alone get on the podium 😎