If you can’t get an answer, you might want to just mock it up and start measuring the port timing. You’ll probably be shooting for 195-198 exhaust duration maybe a little higher (guessing - I’ve never measured an ET). Another method is if you have the correct domes for the setup and know target squish, you can pretty easily figure out how much total spacer with gasket thickness you need. What are you starting with? A top end kit and a crank or a blown up motor or what?