Searching for Stockstad

Hello everyone from a newbie :) I'm searching for pre-emigration information on my gr-grandfather Julius Peter Stockstad (aka Julius Pederson Stokstad). I've been able to determine that he was born in about 1855 in Akershus and came to the US in 1880 aboard the Scythia (according to the Castle Garden website). I do not know though who his parents were and where in Akershus he was born. I believe that Stokstad is a farm name but don't know much beyond that. Can anyone offer advice? Thanks very much, Marcia