The stamping on the starter mounting surface will give you the date that engine (or partial engine / fitted block, etc.) was assembled at Tonawanda. It will not tell you the date the engine was actually replaced in the car -- except that obviously the replacement date had to be after the engine was actually built. But there could be just a couple weeks, or several months, in between.
As to the format of that stamp down by the starter -- T### -- I am having trouble remembering for sure but I think I determined once before that from and after 1-1-1967 that stamp was a Julian date code. So for instance 017 would be the 17th day of an unidentified calendar year, but then the casting date and the CE year stamp tell you what year it was. Again, not positive if I am recalling correctly, but I believe that is right.
Easiest way to tell in the car whether 4 bolt or 2 bolt is to check the size and number of the holes with pipe thread plugs above the oil filter. Take a good pic of those and post it here and we can tell you which you have.
Thanks much !
Numbers near the starter :
Are they cast in or stamped
Can they be seen with starter installed
Above oil filter there is ONE oil pressure pipe plug place . And that is where i put in my mechanical OP gauge tubing , years ago. I read somewhere that those pipe plugs were not 100% accurate for determining 2 or 4 bolt main caps . Admittingly it WILL indicate a damn near all of them though.
One thing that will always confuse me is it had the olden big can and long bolt up thru it oil filter , and i converted it to a spin on with some sort of adapter . Ill get those block date codes BUT if its a 1969 block ( as indicated by the CE 950409 pad stamping ) i had no idea a 69 engine would have that old azz oil filter set up .
I think where all this is headed is :
I have a 427 2 bolt main 390 or 400hp replacement block . Out of what car , ill never know probl.
Square port iron heads and a solid cam , someone put on it .
So i still have to revisit and find :
Block casting date and the assembly date ,, and the clyd head info.
I thank you all for the expertise helping a new guy out , this aint over yet . lol.