John Johnson (Helfstad?) & Family

I am looking for a ship that carried a "John Johnson Helfstad (?)" age about 37 or 38, and his wife Helene or Helena who was at least 5 years older than he, and his son or sons: Peter, born in 1863 and Ole, born in 1864. He arrived in the port of Detroit in June of 1869 and ended up in La Crosse Wiscconsin. Could Helfstad be an Anglisized name for a different Norwegian spelling that sounds about the same. Could it be a farm or place in Norway from which he came?