Yeah - the Chamberlain horizontally opposed created huge crankcase breathing problems. Two 9 inch [at least] diameter pistons with  about 12 inch stroke!Both out, both in at the same time.

Also the heat of the exhaust manifolds coming to a central point, and the difference in expansion and contraction caused manifold gasket problems regularly.

Ours was a petrol/kero model, but I think they also made diesel versions.

Next step in those models were into 2 stroke GM engines - I think 3cyl 71's.  And another unique sound for a tractor exhaust!