Next measure the first cam lobe location from the back side of the cam lobe to the front of the cam journal.
Then
subtract 1/2 the width of the cam lobe to get the lobe center location from the front of the cam.
View attachment 29240
Then measure the second cam lobe location from the back side of the second cam lobe to the front of the cam journal.
Then
subtract 1/2 the width of that cam lobe to get the lobe center location from the front of the cam.
View attachment 29242
What measurements did you get?
The difference between lifter bore centers and the cam lobe centers from the front of the block will be the roller cam lobe offset needed to make roller cams.
The roller cam lobes for the 240/300 roller cams had to be repositioned .095" back from the flat tappet cam lobe locations.