6 cylinder BLOCK casting number, WHERE?
 

Trying to find WHERE these mumbers are to I.D, for parts etc, any help appreciated.

This is the second thread where you've asked this question. I gave you the answer in your other thread, here it is again.

Since you have a 1965 F100 (you failed to mention this-I got the info from your profile), you have either a 240 or 300 I-6.

The SAME block was used for both, so you will have to measure the stroke to find out which I-6 it is. 240 = 3.18" / 300 = 3.98"

Casting numbers on engine blocks are foundry marks, which are usually useless in ID'ing engine sizes, since they cannot be cross referenced to Ford part numbers.

The same scenario applies to most FoMoCo OHV V8 engines from 1952 thru the 1970's.