Over budget 318 build

Maybe I am but not real sure. I posted that chart at the beginning of the thread as well. Just needed some help understanding it. And I’m not sure why your saying .0015-.0020 when the block is .030 over and I’m setting gaps for nitrous. I’ve spoken with my engine builder throughout the machine work (And the direction I wanted to go)which is now done and complete. Now I have the block and am ‘absorbing’ new info with the new challenge ahead by reading and asking opinions of members here willing to help. These guys have done builds like mine before where I haven’t so input is welcomed. Thank you for your input
Ok that chart can be confusing. Here it goes. Skirt clearance is the difference in size between the block and the piston. If the bore is 3.940 (030 over) then the piston should mic 3.938 If you wanted .0020 of skirt clearance. This clearance is finished honed by your machinist and should be different for a nitrous engine vs an N/A engine. I’m saying I wouldn’t run .0020 of skirt clearance on a nitrous engine with KB slugs. I’d want a little more. Rings are another measurement all together. But the same theory applies. More heat (nitrous)=more gap. Make sense now?