[65gto69]

You pretty much have all the info on it, except what car it came out of.

Only things I can tell you from your provided info is that:

"YJ" - Automatic

And normally this engine would have came with #77 heads which are 1965 High performance heads used on 389 blocks in GTO's or 421 HO blocks.

#093 heads were 1966 heads used on 389 blocks in GTO's or 421 HO blocks.

I have heard that late 1965 389 or 421 blocks could have gotten #093 from the factory instead of the #77 heads.

Date code for the heads are located on the outside just below the valve cover mounting pad between exhaust ports. I would think if heads match the block, the head date code should be relatively close to the block date. If the head date code is far into 1966 year than maybe the original #77 heads were replaced at sometime in its life with the #093.

Should have 4 bolt main caps, 4 inch stroke crank, 4.09 bore and 4 bbl carb, and what is called a transfer lug (protruding pyramid cast into the top rear of block) on the passenger side of the distributor pad. You will see it, sticks up about 2 inches. 389's did not have this in that year.

I am sure more people will chime in.

Hope this answers some of your questions.

Mark