hi guys i dont know much about engines or transmissions. or even size for that matter.

i have been interested in building Badland Buggy - Off Road Vehicles - Download Buggy Plans for awhile and it says 26HP tops or 500cc tops but this engine Honda Engines - GX660 4-Stroke Engine is 21HP and 688cc engine. because it is over what they say they want for CC is it to much or would Honda Engines - GX690 4-Stroke Engine be even better more HP same CC?

kk on to another question this would be my first build and i have already been recommended to use a ATV or snowmobile engine but would the honda be a better choice because this is like a go kart with role cage and not a full on buggy?

i was also recommended to have a reverse can you put a reverse on that type of engine? if so how big of a transmission would it be?

thanks for taking the time to read