Todd is correct as far as fishing info from a few forums,
but I have found the most accurate info has been here.
I also watch the other forum and acscc.
....Maybe 35hp ,,kinda tame for 1977...the front section
of sliders didn't push down much and tended to be stable
for its width since it really only pushed hard on skis and
rear end to hard snow trails...after market ski spreaders
just bent tie rods , spindles and skis..
The vent in left side of hood was really for the hyd drives
but they left it there to get more air under the hood.The
RH vent pulled air directly into recoil for engine cooling
and also general debris which stuffed tight in a hidden
corner in Mag side head and eventually over heated the
motor.....take a comp gauge with you and remove recoil
if you buy and remove all debris and mouse nests with
a bent cloths hanger....
Why did you want this model ?
good luck
Ron