I bought front rotors (which contain the hub) as well as front wheel bearing. This allowed me to measure the front track, and as advertised it was 54″. Strangely enough, with wheels in place on the rear axles, I measured a track of 63″ vice the 60 I was expecting. It may be a difference in wheel back spacing. In any event I have decided to build with the rear end I have, and keep the front suspension stock until the last minute. The inboard spring idea is practicable, but will be easier once I can fit up the engine.
Measured front and rear track