new motor

[scotty]

hi i have a 1988 argo 8x8 it has a 18hp kohler in it and i am wondering what the biggest motor i can get in it without cutting the body at all i can get a 18hp briggs for almost nothing would this be a good choice. my second question is im going to change the tranny oil in it and want too know what oil to put in it should i use 75 90 synthetic

[whntr]

New motor

I mounted a Honda Gx620 twin 20 hp in my older TB 8 wheeler. The only difficulty was it required a different length of belt. Seems to have adequate power and I have always liked Honda reliability.