I have a kyosho ag wagon and would like a four stroke. I have a hanger 9 80" cub with a 50 saito engine. I really love the engine. It is so reliable. I am thinking about the saito 72 or 82. I want some real muscle. Just worried about this engine being too big for cowl. Please let me know if anyone has one of these engines or any that would be suitable. I still cant believe I found this arf nib. Someone told me that a saito 62 would be all that I need

A 72 or 82 will stick out the side of the cowl. You MIGHT be able to fit it inverted without cutting the cowl, but then you have to deal with an inverted engine.

If it were me, I'd just cut the hole and mount it horizontally

Great airplane BTW

Do you think these engines will be too big?

Cessna, An inverted four stroke is a non-issue. (two strokes are a horse of a different color). My personal experience is that a 72 is slightly smoother than an 82. Prop clearance might be an issue. It has been a while since I've had one of the Agwagons in my hands but I do not believe a 72 would be too big physically. Maybe one of the new 62's would fit your purpose.
Fred

Go with a YS 63

It will have just as much power as the Saito 72. YS engines will idle very slowly and are very reliable, as well as more fuel efficient than those Saito's. Granted they are little more expensive, but very worth it. I only use YS engines now when looking 4 stroke.
Just my two cents.

SM

I dont have a lot of experience with 4 strokes but a think a 40 - 45 size 2 stoke would out perform my 50 saito that I have on my cub. I really want a four stroker on this agwagon. My old saito sounds, runs, and idles great. It never fails. I just want to make sure I get enough engine so it is not under powered but at the same time I dont want to over do it. Also, what would be the possibility of a smoke system? This plane is supposed to weigh 6lbs and has a wingspan of 69". A 40 - 46 2 stroke is recomended. All help is greatly appreciated.

Lowering the fuel tank will also help with an inverted engine