I've been discussing this over on Wings Over NZ for a while trying to get a grip on what was required so think I have fair idea what is required. I picked up some plans on Britmodellerhttps://www.britmodeller.com/forums/index.php?/topic/234909836-hudson-to-lodestar-conversion/&tab=comments#comment-926252
I have Classic Airframes Hudson (kindly sold to me by group member) to use as pattern for the new engines and nacelles. I've checked the wings and engine centre lines between the Ventura and Lodestar match which was one thing I was not certain about. This shows Hudson wing over Ventrua wing.
I may even be able to adapt the alternative cowlings provided with the Hudson.