Well, I now have another project, YeeHawaaaaa. Too many projects and too little time. The 261 is in the back of the ol '95 ..... Cummins 3500. We were barely able to load it with the collapsible lift the previous owner had. We were just able to get it into the bed far enough to close the tailgate. Sure made for a better ride.
Per Deve's GM Engine Casting Number list I have a 3733950 Chevrolet 55-57, 261. Where have I seen that number.....Oh, on Johns engine picts a few post above (Insert happy faces here).
Numbers are; just above the starter; CON L159
In front of the fuel pump, just above the pan; 3733950
On the head; 3836850 GM5
Pulled the carb and the intake/carb opening is 1.75"
Based on my recent new found knowledge I "think" I have a no Captains Bars, 261 cast in the '54 block mold as John described above. I didn't pull the valve cover or do a compression test or do any of the prepurchase checks mentioned but the engine just looks good. By looking in the oil hole in the valve cover I could that the valve train still has oily looking oil on it and not just a bunch of dried up crud. After I finish a couple or three pressing projects I'll start the assessment of my new to me 261 engine.
PS, if this isn't a hen's tooth of a 261 please let me down easy!!!