I've drilled the blocks so a Holley jet wil fit and I've done the same thing to the heads, your choice The Indy heads have seperate oil lines from the back of the block oil galley passages to each head, not sure if you knew about that. My message is the blocks I have restricted had grooved cam journals, .030 wide and close to .030 deep, not the same flow capicitys as the external oil lines like the Indy heads use I would, and have, use a .060 in the block first, way better to have a little to much oil feeding than not quite enough