I have a 351w motor block that is clearly not original in a 1963 Flareside Custom Cab. How can I tell when the engine was manufactured? I need more information on what I have before I can figure out what needs to be done to the engine. There is no pollution control on the vehicle at all. Are there any ID numbers on the motor? If so, where? Any help on how to ID this motor would be greatly appreciated. Thank You!

 

On the block, just above the driver side waterpump outlet, or just to the right and below the distributor boss, you'll find a small section of the deck sticking out. Providing the block was not drasticaly decked, you should find a five digit number stamped into the deck.
For example, "9A12S". The first letter "9" stands for the calander year, in this case, 1969. The second digit "A" stands for the month of manufacture, in this case, January. February would be "B", and so on. The month letters run A thru M, note the letter "I" is not used. The next letter or two stand for the day of manufacture. In this case, "12" would be the 12th. Complete date, January 12, 1969.