Kubota or Yanmar, that is the question
 

So I've been doing research and can't really decide which is a better engine.
kubota or yanmar? Any suggestions?

no comparison
 

3tna72 yanmar, hands down. Can be found in jd f900 series and in i believe 755 jd utility tractors. Only downfal that motor you have to get internals from deere only. Spun'em over 6000 rpm with aftermarket injection pump and turbo.

Do you know the size of that one? I found a little yanmar out of a 332 John Deere.
I forget the size of the engine.

how big you say?
 

I believe the 3tna72 is about 880cc and 22hp, the 332 should be a 3tn66 and 710cc and only 16hp. Dont quote me but I am pretty sure of those numbers.

Actually I checked on it after I asked and you're right.
it's hard to find one of these motors. I did find one but its across the country!
Now would the 3tna72 be better than the 3tn66 just cause of the size?

does size REEEAAALLLYY matter?
 

In the world of pulling there is no replacement for displacement. I'm not sure what the major differences in build are between the two motors, But I know what we put ours through.

Well some clubs like to limit you on displacement, but how are they to know what it has? I've been looking for aftermarket pumps and have had no luck... is that a special order? Same goes for the turbo... I was thinking of getting a Turbo from a Dodge spinter van. They aren't to big of a Turbo I think. Now for a clutch, what did you guys use? I've seen the clutches You can get for kohlers. They support like up the 60hp, but I'm assuming the little yanmar will make more than that?

A Dodge Sprinter is very large...the turbo'd Kubotas I've seen use the turbo from a Smart car.

It all depends on how much fuel is being pushed through it if it'll spin that sprinter Turbo. Not to mention some internal work. Do you know the specs of a smart car Turbo?? I'm guessing its smalled than a grown mans fist!

I don't know the specs. You don't want to over-boost the engine. I don't know much about these, and I'm guessing a lot of people on this forum don't either. You might want to look for a garden tractor pulling forum.