Little more about Avanti. I asked around in Sweden and got an answer from Kjell Ahlqvist the owner of the eminent site over Swedish bikes http://www.cykelhobby.com/
He told that Avanti was a try from Swedish Monark to sell bikes in USA during the early 1960. They named the bikes Avanti because it already was a bike brand which was named Monark in USA.
It is little strange in English Monark should be Monarch, but apparently had USA during the early 1960 both a brand called Monark and one called Monarch?
On the Avanti Track bike was the Sweden decal spelled Schweden, Schweden is Sweden in German. Maybe was that bike made for the German market.
Best regards
Peter Söderlund
Gothenburg
Sweden