Engine identification

[JNS]

I've just read Miles Wilkins book about the Twin-Cam engine. In Part 3 'Engine Identification' he gives a list of engine serial No. prefixes. Does anyone know where on the engine this is?
 Also after 1968 the cylinder heads carried one of 3 letters, H, N, or S, stamped on the raised boss in front of No.1 spark plug, but mine is blank.
 The car is a '71 Twin cam.
 I would appreciate any thoughts.
Jeff

[surfguitar58]

I believe it is on the right side engine mount, it is very faint and hard to see.
t

[Grumblebuns]

There are numbers on the lower left corner of the block that has a small rectangular plate or stamping that I believe should be the same as the number on the stamped om the manufacturer plate on the front plenum.   

[JNS]

Thats great.
Thanks for the replys.
Jeff

[literarymadness]

The engine serial number located by the motor mount (like Surf already said) is the one that corresponds to the prefixes referenced in the Miles book and to the one on the I.D. Tag. Here is a photo of mine that the number is a little clearer.  Mine begins with an "S". I am guessing that yours will either begin with "Q" or "V". But I would check the I.D. Tag first.