I had my hands on a replacement 1850 baseplate recently. Check out the position of the secondary transfer slots relative to the throttle blades in this Holley stock photo. Can't see how this would work at all, as the blades need to be pretty far open to get anywhere close to the transfer slot. An original plate has the slots close to the blades when they are closed. I can assume that Holley is shipping 1850s this way and that the secondaries likely have a massive bog that cannot be tuned out.