Locating engine serial number

[babylikes2rockit]

Does anyone have some ideas of

Does anyone have some ideas of where to locate the engine serial numbers on twim chevy 350's. Was told these were crusaders but having some doubt now. Looking to find owner and service manual but can't figure out what year these are. The surveyer couldn't locate the serial numbers and the numbers I located don't look like they are crusader numbers. I think they may be the manifolds casting number or something.

 

[silverton_34]

There should be an info plate

There should be an info plate located on the back of the block between the heads unless someone removed it for some strange reason. Mine was there but painted over several times. Had to use acetone and a lot of scrubbing to reveal the info.