The outer row of head bolts bosses on a BB are nominally 1.00” thick.
Measure several of then and average the numbers.
However much thinner they are than 1” will be very close to how much has been cut.
Gonna be a challenge to do with heads installed & in the car.
What you’re experiencing is why it’s a good idea to cut the intake side of the heads the appropriate amount when the decks are cut.
