Small Block Oiling System Mods

I assume you mean the height of the lifter bore. Isn't that pretty standard? Are there significant variance in the depth or height of the lifter bore.

You're right, for me it's a shade too late. Actually, they are my old lifters being placed into a fresh block. We chose not to perform the tube process due to the recommendation of not only the cam companies, but a couple of small block builders as well. I did not actually check the bore with the cam installed. Do you think that even if I have good pressure the problem would be lack of volume downstairs?