How do I find out the year of my oldsmobile 260 engine?

I have an Oldsmobile 260 Engine in My 1986 Regal. I need to find out what year it is. I have the vin number to the engine which is 557751-2B. Is there a website where I can find this out? Or can someone give me a source where I can find this answer?? Your help is greatly appreciated, Thank you.|||The 4.3 260 was used in the late 70's. Not sure why someone would put one in a car that late. The factory V8 option for that car would have been the 5.0 307 which was also an Olds so the 260 would in theory be a bolt in swap. I think the 260's used the 4bbl intake with the 'dual jet' carbs which were quadrajet bodies with the secondaries blocked out. The 307's had the computer controlled q jets.|||There is a casting date on the back of the engine where the transmission bolts on. ALL GM engines have a foundry casting date somewhere on the block . If your car is a 1986 it could have a 1985 casting date but obviously not a 1987 date. Hope this helps