Marquette Marque 8 Engine analyzer

I acquired this analyzer 25+ years ago, plugged it in , hooked it up to a car I owned and everything worked. Parked it in my garage and forgot about it. It comes with a spare (new) picture tube. It has a scroll mechanism with 2 scrolls that have specs on them going back to the early 50s. This thing has an Art Deco look to it and is WAY past it's useable prime but would go good in a man cave or museum like display. It's going to take a bit to dig it out so expect better photos when the weather is better. I have no idea of it's value but I am open to trades.