The simple answer is its cheaper to buy a new set. Unless you actually do the work yourself or the new caps are not available when you need them. Definitely more work for your engine builder.
1" Cruz champion intake plenum spacer with gaskets NEW . $75 shipped to lower 48
Pair New rubber intake seals $20 shipped
Pair of new in the box peachstate T Type die-cast cars. 8006 & 8002. Looks like something is on one of the boxes. $300 shipped
You are over thinking this. If you run pump gas you will denotate and need to run forged.
I have bought several second hand NEW sets or slightly used for around $400-600
No, your machinist will bend you over for doing that.
They want new parts to work with. Unless you had 10 rear caps to test fit and one was close.
You will pay 3x to 4x what you think you are saving on the new rear cap.