What engine is in a power unit with a 3Sxxxxx on the tag? Is this a D315? Thanks for any help.

My book shows 3 different engines with the 3S SN & they are a 3S D17000 & they would be a big industrial V-8 engine & the next is a 3S D13000 industrial engine which would be the same basic engine as the old D8s used & the little engine a D3400 3S industrial engine is same basic one used in the early D2 tractors. They were a much older engine than the D315 & smaller as they were only a 3 3/4" bore engine where the D315 were a 4 1/2" bore.

This is a 4 cylinder so it would probably be the D3400 then. Thanks.