Engine confusion

Hi, y'all. I always wanted to own a vintage tractor to restore and admire. since I live in a subdivion buying a large tractor seemed a little like overkill as I wouldn't have much use for the finished project. After years of drooling over other folks vintage tractors, I finally purchased my very own about two monthes ago. It is a 1970 suburban 12 that runs great and has a fairly strait body but needs paint and tlc. It only came with a small set of plows. No deck or anything else. I fell in love with it but to be honest it only open a flood gate. Since that time I have purchased a 1968 Cub cadet 72 that has been refitted with a 12hp Tecumseh at some point. It is in need of a full restoration and I am still working on hearing it run for the first time. What a glorious day that will be! Then just a couple days ago I found a Suburban ss12 on craigslist and I had to have it. It came with several emplements and it has a very solid and fully functional deck on it! I said all this to ask a question. While I'm by no means new to small engines and lawn equipment seeing that for many years I have been buying, repairing and resaling all kinds of small engine equipment, I am new to these vintage tractors. I figured right away that the engine on my newest toy isn't original. first off I noticed it had a conventional sytle starter instead of the starter/generator found on the suburbands from this era (or so I think from the research I've done). This got me curious so I looked up the numbers I found on the engine and it appears to be a 14hp Tecumseh. I need some of y'alls great knowledge to help me determine what engiine I have, what year it may be and if it was ever offered on a suburban. By the way the engine runs perfectly. The numbers I found are as follows: OH140 1600 336 SER 0047E. If anyone can help me I would be grateful

Well after a good deal of research I was able to make some sence out of interpreting the engine code. Most of you probably are far ahead of me in knowing this but for those who may not know here is my interpretation of what I found. My engine code is OH140 1600 336 SER 0046E. The OH means over head valve cast iron block. The 140 means 14hp (oviously not the original engine seeing that my tractor is a ss12). the 1600 336 is the part reference number. the first letter of the last four digits is the year. after 2004 the manufacture code had five numbers instead of four. The only thing I haven't figured out is finding the exact year because any year ending in 0 before 2004 is a possibility. I'm almost positive that I can rule out it being a 2000 or 1990 model. so that leaves 1970 or 1980 . Since this engine has the newer style starter that the engine on my other suburban 12 (I'm 99% sure it has the original motor), I'm swinging towards 1980. the actual month and day are found in the last three digits of the pre 2004 code. I didn't figure out exactly how to decipher that part yet . the letter E on the end is the actual prodution line the engine came off of.
If anyone has corrections to this post please let me know. PS sorry for the spelling; I'm at a loss without spell check