How to ID 421, 428, 455 Poncho engines?

I know where a bunch of Poncho engines are, but I'd like to know how to ID the "good ones", that is, the 421's, 428's, and 455's. What do I look for? What numbers? And where?

 

I think in the early 60's they started casting in the size on the drivers side of the block. up towards the front.

this might help

http://www.boyleworks.com/ta400/psp/blockID.html

 

The year of the block was cast into the distrbutor pad, and the displacment is located on the left side of the block, below the exhaust port of the #1 cylnder. hope this helps

 

Sorry, Rev. I didn't see the link you posted... Your link give more specific info on block I.D.

If you do find a 421 or 428, you are a very luck man!!